Transparent conductive film and method for producing transparent conductive film

ABSTRACT

A transparent conductive film comprises a transparent substrate and a metal wiring portion formed thereon. A thin metal wire contained in an electrode portion in the metal wiring portion has a surface shape satisfying the condition of Ra 2 /Sm&gt;0.01 μm and has a metal volume content of 35% or more. Ra represents an arithmetic average roughness in micrometers and is equal to or smaller than the thickness of a metal wiring located in a position where the surface roughness is measured. Sm represents an average distance between convex portions and is 0.01 μm or more.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY CLAIMS

This application is a Divisional of U.S. application Ser. No. 14/947,831filed on Nov. 20, 2015, which is a Continuation of InternationalApplication No. PCT/JP2014/062783 filed on May 14, 2014, which waspublished under PCT Article 21(2) in Japanese, which is based upon andclaims the benefit of priorities from Japanese Patent Application No.2013-110402 filed on May 24, 2013 and Japanese Patent Application No.2014-045684 filed on Mar. 7, 2014, the contents all of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a transparent conductive film and amethod for producing a transparent conductive film.

BACKGROUND ART

Metals have high conductivity and therefore are suitable for use in amaterial for a conductive layer. But at the same time, the metalsintensely reflect visible lights, and are unsuitable for use inapplications such as touch panel applications, in which a visibleelectrode pattern is considered as a critical defect. Therefore, atransparent conductive oxide such as ITO (Indium Tin Oxide) has beenused conventionally in such applications.

Meanwhile, a metal, which has advantages including patterning easiness,excellent flexibility, and low resistance over the oxide, has beenstudied as an alternative to the ITO. In recent years, it has been foundthat the problem of the visible metal wiring can be reduced to someextent by thinning the metal wire or by modifying the pattern.

Conventional technologies for thinning the metal wire include atechnology containing using a metal nanowire in a transparent conductivefilm as described in Japanese Laid-Open Patent Publication No.2009-505358 (PCT) etc. and a technology containing, utilizing aphotographic material technology, exposing and developing aphotosensitive material having a silver salt emulsion layer to produce atransparent conductive film. However, in the technologies, theelectrical resistance of the resultant wiring is higher than theinherent resistance of the metal disadvantageously, e.g. because a largenumber of contact points are formed between fine metal particles.

To solve this problem, technology development has been actively studiedon a calender treatment (Japanese Laid-Open Patent Publication No.2009-004726), a photo-fusion treatment (Journal of Electronic Materials,2011, 40, 2268-2277, J. S. Kang, J. Ryu, H. S. Kim, H. T. Hahn,Sintering of Inkjet-Printed Silver Nanoparticles at Room TemperatureUsing Intense Pulsed Light), and the like. However, these treatments aredisadvantageous in that metallic reflection is enhanced to make aconductive film pattern further visible.

For example, as a technology for making the conductive film pattern lessvisible, Japanese Laid-Open Patent Publication No. 2011-082211 disclosesa method for preventing the reflection from the conductive pattern,which contains stacking a blackening layer having a thickness of 0.01 to0.5 μm on a surface of a conductive pattern layer. However, in thetechnology of Japanese Laid-Open Patent Publication No. 2011-082211,conductivity reduction cannot be avoided in principle disadvantageously.Incidentally, a technology for giving an antiglare function to anantireflection film has been known (see Japanese Laid-Open PatentPublication Nos. 2005-070435 and 2004-004404).

SUMMARY OF INVENTION

As described above, due to the inherent reflection of the metal, thethin metal wire is visually detected easily in the transparentconductive film or the like, and the thin metal wire pattern is highlyvisible. Though the thin metal wire can be made less visible by thinningthe wire or by modifying the pattern, this method tends to result in anincreased electrical resistance. Though the resistance can be reduced byincreasing the volume content of the metal in a calender treatment orthe like, this treatment results in a significantly increased lightreflection. Thus, it is difficult to achieve both an appropriatevisibility (low visibility of the wiring pattern) and a low resistance.

In view of the above problems, an object of the present invention is toprovide a transparent conductive film, which can achieve both of anappropriate visibility and a low resistance due to a specific surfaceshape of a thin metal wire, and thereby can be suitably used in a touchpanel, a display device, or the like.

Another object of the present invention is to provide a method forproducing a transparent conductive film, which uses a calender with apressing surface having appropriate material and surface, and therebycan achieve both an improved visibility and a low electrical resistancein the transparent conductive film.

A further object of the present invention is to provide a touch panel,which has a wiring pattern less visible on a display screen, and has alow electrical resistance and an excellent wiring adhesion, therebyresulting in high reliability.

A still further object of the present invention is to provide a displaydevice, which contains a transparent conductive film on a displayscreen, has a less visible wiring pattern in the transparent conductivefilm, and has a low electrical resistance and an excellent wiringadhesion, thereby resulting in high reliability.

The inventors started to make a study on the use of the methodcontaining pressing a concave-convex surface against a sample surface toachieve an antiglare function (see Japanese Laid-Open Patent PublicationNo. 2005-070435, etc.), for a transparent conductive film obtained byexposing and developing a photosensitive material having a silver saltemulsion layer.

In experiments, various surfaces were pressed against samples. As aresult, it was found that most of common calender rollers caused thefollowing problem. That is, light reflection could not be reduced, or athin metal wire was broken though the light reflection could be reduced.As a result of further research, the inventors have found that aspecific pressing surface having particular material and shape canachieve both light reflection reduction and resistance reduction in athin metal wire. The present invention has been accomplished based onthis finding.

Accordingly, the present invention includes the following components.

[1] According to a first aspect of the present invention, there isprovided a transparent conductive film comprising a support and a metalwiring portion formed thereon, wherein at least a part of the metalwiring portion has a surface shape satisfying the condition ofRa²/Sm>0.01 μm and has a metal volume content of 35% or more. Rarepresents an arithmetic average roughness [μm] and is equal to orsmaller than the thickness of a thin metal wire located in a positionwhere the surface roughness is measured. Sm represents an averagedistance [μm] between convex portions and is 0.01 μm or more. Thedefinitions are applied also in the following description.

In general, a conventional metal wiring portion has a luster surface.Therefore, the surface intensely reflects a visible light, and the ratioof the specularly reflected light to all the reflected lights (specularreflectance) is increased. As a result, the thin metal wire in at leastthe part of the metal wiring portion is highly visibledisadvantageously. In addition, in a case where the thin metal wire hasa low metal volume content, though the incident light is introduced intospaces between metal particles to lower the specular reflectance, themetal particles exhibit a loose connection, thereby resulting in a highelectrical resistance disadvantageously. The electrical resistance ofthe thin metal wire can be lowered by performing a calender treatment orthe like to increase the metal volume content. However, the metalparticles are densely arranged on the surface, whereby the specularreflectance is significantly increased and the thin metal wire is madehighly visible disadvantageously. Thus, it is difficult to achieve bothan appropriate visibility (the thin metal wire being less visible) and alow resistance.

In contrast, in the first aspect of the present invention, at least thepart of the metal wiring portion has the surface shape satisfying thecondition of Ra²/Sm>0.01 μm. In this case, the ratio of the scatteredlights is increased and the specular reflectance is lowered, whereby thethin metal wire is less visible. Thus, even when the metal volumecontent is increased to 35% or more, the light reflection from the metalwiring portion can be reduced. Consequently, both of the appropriatevisibility (the thin metal wire being less visible) and the lowresistance can be achieved.

In the present invention, the surface shape (the surface roughness) ismeasured by a measuring apparatus having a spatial resolution of higherthan 0.03 μm in the height and horizontal directions. Specifically, alaser microscope having an objective lens having a magnification of 100or more is used, and an area of 100 to 300 μm is subjected to themeasurement. Stylus-type surface roughness meter cannot be used for thesurface roughness measurement in the present invention because of lowspatial resolution.

[2] In the first aspect, it is preferred that at least the part of themetal wiring portion has Sm of 4 μm or less. In this case, the specularreflectance can be reduced to 1.2% or less.

[3] In the first aspect, it is preferred that at least the part of themetal wiring portion has a difference of less than 3% between thespecular reflectances of its front surface and its back surface. Thesupport has a surface having the metal wiring portion and the oppositesurface, and the back surface of the metal wiring portion is the surfacethat can be observed from the opposite surface side through the support.The specular reflectances are determined by subtracting the reflectanceat the interface between air and the support.

This is effective, for example, in a case where metal wiring portions(first and second metal wiring portions) are formed on the front andback surfaces of one support respectively.

In the transparent conductive film, the front surface of the first metalwiring portion and the back surface of the second metal wiring portion,which is observed through the support, have a specular reflectancedifference of less than 3%. Therefore, the thin metal wire in the firstmetal wiring portion is less visible, and the thin metal wire in thesecond metal wiring portion is also less visible. Consequently, even ina case where the metal wiring portion is formed on each of the front andback surfaces of one support, the transparent conductive film can havean improved visibility, and the first and second metal wiring portionscan have a low resistance.

[4] According to a second aspect of the present invention, there isprovided a method for producing a transparent conductive film comprisinga step of forming a metal wiring portion on a support and a calenderstep of pressing a metal member having a concave-convex surface againstat least a part of the metal wiring portion, wherein the surface of themetal member has a shape with Ra²/Sm of more than 0.015 μm.

In this method, a transparent conductive film, which contains at leastthe part of the metal wiring portion having a surface shape satisfyingthe condition of Ra²/Sm>0.01 μm and a metal volume content of 35% ormore, can be easily produced.

[5] According to a third aspect of the present invention, there isprovided a method for producing a transparent conductive film comprisinga step of forming a metal wiring portion on a support and a calenderstep of pressing a metal member having a concave-convex surface againstat least a part of the metal wiring portion, wherein the surface of themetal member has such a shape that Sm is equal to or smaller than theline width of a thin metal wire in at least the part of the metal wiringportion, Ra is equal to or smaller than ⅙ of the thickness of the thinmetal wire measured before the calender step, and Ra²/Sm is more than0.015 μm.

In this method, a transparent conductive film, which contains at leastthe part of the metal wiring portion having Sm of 4 μm or less, asurface shape satisfying the condition of Ra²/Sm>0.01 μm, and a metalvolume content of 35% or more, can be easily produced.

[6] According to a fourth aspect of the present invention, there isprovided a method for producing a transparent conductive film comprisinga step of forming a metal wiring portion on a support and a calenderstep of conveying a resin film having a concave-convex surface togetherwith the metal wiring portion to press the resin film against at least apart of the metal wiring portion, wherein the surface of the resin filmhas a shape with Ra of more than 0.15 μm.

In this method, a transparent conductive film, which contains at leastthe part of the metal wiring portion having a surface shape satisfyingthe condition of Ra²/Sm>0.01 μm and a metal volume content of 35% ormore, can be easily produced.

[7] In this case, it is preferred that the surface of the resin film hasa shape with Ra²/Sm of more than 0.01 μm. In this method, a transparentconductive film, which contains at least the part of the metal wiringportion having Sm of 4 μm or less, a surface shape satisfying thecondition of Ra²/Sm>0.01 μm, and a metal volume content of 35% or more,can be easily produced.

[8] According to a fifth aspect of the present invention, there isprovided a method for producing a transparent conductive film comprisinga step of forming a metal wiring portion on a support having aconcave-convex surface, wherein the surface of the support has a shapewith Ra of more than 0.15 μm and has Ra²/Sm of more than 0.02 μm.

In this case, the metal wiring portion is formed on the surface of thesupport, whereby the concave-convex shape of the support surface istransferred to the surface of the metal wiring portion. Thus, also inthe method containing forming the metal wiring portion on theconcave-convex surface of the support, the properties that at least thepart of the metal wiring portion has a surface shape satisfying thecondition of Ra²/Sm>0.01 μm and has a metal volume content of 35% ormore can be achieved. Consequently, this method is capable of producingthe transparent conductive film with a more excellent visibility ascompared with a method of forming a metal film on a smooth surface.

[9] In this case, the step of forming the metal wiring portion on thesupport may contain vapor-depositing a metal on the surface of thesupport. In this method, a transparent conductive film, which containsthe metal wiring portion having a surface shape satisfying the conditionof Ra²/Sm>0.01 μm and a metal volume content of 35% or more, can beproduced.

[10] Alternatively, the step of forming the metal wiring portion on thesupport may contain plating the surface of the support with a metal.Also in this case, a transparent conductive film, which contains themetal wiring portion having a surface shape satisfying the condition ofRa²/Sm>0.01 μm and a metal volume content of 35% or more, can beproduced.

[11] In the second to fifth aspects, at least the part of the metalwiring portion may have a mesh pattern containing a thin metal wire.

[12] According to a sixth aspect of the present invention, there isprovided a transparent conductive film obtained by the production methodaccording to any one of the second to fifth aspects.

[13] In the first and sixth aspects, at least the part of the metalwiring portion may have a mesh pattern containing a thin metal wire.

[14] In the first and sixth aspects, the transparent conductive film maybe obtained by a production method containing an exposure step ofexposing a photosensitive material having the support and a silver saltemulsion layer formed thereon and a development step of developing theexposed silver salt emulsion layer to form a conductive patterncontaining a metallic silver portion on the support.

[15] According to a seventh aspect of the present invention, there isprovided a touch panel having the transparent conductive film accordingto the first or sixth aspect.

In this case, in a case where the touch panel is attached to a displayscreen, the wiring pattern is less visible, and the transparentconductive film exhibits a low electrical resistance and an excellentwiring adhesion, thereby resulting in high reliability.

[16] According to an eighth aspect of the present invention, there isprovided a display device having the transparent conductive filmaccording to the first or sixth aspect.

In this case, the transparent conductive film is attached to the displayscreen of the display device, the wiring pattern is less visible, andthe transparent conductive film exhibits a low electrical resistance andan excellent wiring adhesion, thereby resulting in the display devicewith high reliability.

As described above, in the transparent conductive film of the presentinvention, the thin metal wire has a specific surface shape, wherebyboth of the appropriate visibility and the low resistance can beachieved. Thus, the transparent conductive film is suitable for use inthe touch panel or the display device.

In the transparent conductive film production method of the presentinvention, the pressing surface of the calender contains an appropriatematerial and has a specific surface shape, whereby both of theappropriate visibility and the low resistance can be achieved.

Furthermore, in a case where the touch panel of the present invention isattached to the display screen, the wiring pattern is less visible, andthe transparent conductive film exhibits a low electrical resistance andan excellent wiring adhesion, thereby resulting in high reliability.

In addition, in the display device of the present invention having thedisplay screen and the transparent conductive film attached thereto, thewiring pattern is less visible, and the transparent conductive filmexhibits a low electrical resistance and an excellent wiring adhesion,thereby resulting in high reliability.

The above objects, features, and advantages of the present inventionwill become more apparent from the following description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a partial cross-sectional view of a transparent conductivefilm according to an embodiment of the present invention, placed on adisplay panel of a display device;

FIG. 1B is a partial plan view of the transparent conductive film;

FIG. 2A is an explanatory view for illustrating a behavior of aconventional thin metal wire having a luster surface (with a highspecular reflectance);

FIG. 2B is an explanatory view for illustrating a behavior of a thinmetal wire according to this embodiment having a concave-convex surface(with a low specular reflectance);

FIG. 3A is an explanatory view for illustrating a behavior of aconventional thin metal wire having a low metal volume content (with alow specular reflectance);

FIG. 3B is an explanatory view for illustrating a behavior of aconventional thin metal wire having a high metal volume content (with ahigh specular reflectance);

FIG. 4 is a graph plotting a specular reflectance change with respect toRa²/Sm of an electrode portion;

FIG. 5A is a partial cross-sectional view of metal wiring portions (afirst metal wiring portion and a second metal wiring portion) formed onthe front surface and the back surface of one transparent substraterespectively;

FIG. 5B is a partial cross-sectional view of a stack of two transparentconductive films (a first transparent conductive film and a secondtransparent conductive film);

FIG. 6A is an explanatory view for illustrating a first method of acalender treatment;

FIG. 6B is an explanatory view for illustrating a second method of thecalender treatment;

FIG. 7 is a graph plotting a specular reflectance change with respect toRa²/Sm of a pressing surface of a metal roller in each of a case wherethe Sm value of the metal roller is equal to or smaller than the linewidth of a thin metal wire and a case where the Sm value of the metalroller is larger than the line width;

FIGS. 8A and 8B are each an explanatory view for illustrating therelationship between the Sm value of a metal plate or a metal roller andthe line width of a thin metal wire;

FIGS. 8C and 8D are each an explanatory view for illustrating therelationship between the Ra value of the metal plate or the metal rollerand the thickness of the thin metal wire;

FIG. 9 is a graph plotting a specular reflectance change with respect toRa²/Sm of a pressing surface of a resin film;

FIG. 10A is a plan view of a mesh pattern electrode formed in a meshsample;

FIG. 10B is a plan view for illustrating the size of a square lattice inthe mesh pattern electrode; and

FIG. 11 is a graph plotting the results of Examples 1 to 3, ComparativeExamples 3 to 6, 13, and 14, and Comparative Examples 7 to 11, where theabscissa represents the Ra value of a pressing surface of a metal plateand the ordinate represents the Sm value of the pressing surface.

DESCRIPTION OF EMBODIMENTS

Several embodiment examples of the transparent conductive film, theproduction method, the touch panel, and the display device of thepresent invention will be described below with reference to FIGS. 1A to11. It should be noted that, in this description, a numeric range of “Ato B” includes both the numeric values A and B as the lower limit andupper limit values.

As shown in FIG. 1A, a transparent conductive film 10 according to anembodiment of the present invention has a transparent substrate(support) 12 and a metal wiring portion 14 formed on a surface 12 a ofthe transparent substrate 12. For example, the transparent conductivefilm 10 is attached to a display panel 16 a of a display device 16.Thus, the transparent conductive film 10 may be used as anelectromagnetic-shielding film of the display device 16, a transparentconductive film of a touch panel, or the like. Examples of such displaydevices 16 include liquid crystal displays, plasma displays, organic EL(electroluminescence) displays, and inorganic EL displays. Thetransparent conductive film 10 may be placed inside the display device16 and integrally combined with the display device 16.

The metal wiring portion 14 contains an electrode portion 18, which maybe used in an electrode in the electromagnetic-shielding film, the touchpanel, or the like, and further contains a wiring portion 22 having alarge number of metal wirings 20, which may be used for supplying adrive signal to the electrode portion 18 or transmitting a signal fromthe electrode portion 18. As shown in FIG. 1B, for example, theelectrode portion 18 has a mesh pattern 28, and a large number oflattices 26 containing a thin metal wire 24 are arranged in the meshpattern 28. The metal wirings 20 and the thin metal wire 24 contain, forexample, a metal mainly composed of gold (Au), silver (Ag), or copper(Cu).

The line width Wa of the metal wiring 20 and the line width Wb of thethin metal wire 24 satisfy the relationship of Wa≧Wb, and the thicknessto of the metal wiring 20 and the thickness tb of the thin metal wire 24satisfy the relationship of ta≧tb. In particular, the side length La ofthe lattice 26 containing the thin metal wire 24 in the electrodeportion 18 is preferably 100 to 400 μm, more preferably 150 to 300 μm,most preferably 210 to 250 μm. In a case where the side length La of thelattice 26 is within the above range, the transparent conductive film 10has a high transparency and thereby can be suitably used on the displaypanel 16 a of the display device 16 with excellent and comfortablevisibility. The lattice 26 may have a shape of square, rectangle,parallelogram, rhombus, or polygon such as hexagon or octagon.

The line width Wb of the thin metal wire 24 may be selected within arange of 30 μm or less. In the case of using the transparent conductivefilm 10 as the electromagnetic-shielding film, the line width Wb of thethin metal wire 24 is preferably 1 to 20 μm, more preferably 1 to 9 μm,further preferably 2 to 7 μm. In the case of using the transparentconductive film 10 in the touch panel, the line width Wb of the thinmetal wire 24 is preferably 0.1 to 15 μm, more preferably 1 to 9 μm,further preferably 2 to 7 μm.

The transparent conductive film 10 of this embodiment may be used in aprojected capacitive touch panel, a surface capacitive touch panel, or aresistive touch panel. The transparent conductive film 10 may be usedalso as an optical film on the display panel 16 a of the display device16.

In the transparent conductive film 10 of this embodiment, at least theelectrode portion 18 in the metal wiring portion 14 has a surface shapesatisfying the condition of Ra²/Sm>0.01 μm and has a metal volumecontent of 35% or more. In this condition, Ra represents an arithmeticaverage roughness [μm] and is equal to or smaller than the thickness ofthe thin metal wire located in a position where the surface roughness ismeasured. Sm represents an average distance [μm] between convex portionsof 0.01 μm or more. The metal volume content is calculated using theamount M [g/m²] of the metal per unit area, the specific gravity d[g/m³] of the metal, and the average thickness H [m] measured in an SEMimage of a cross section. Thus, the metal volume content is calculatedby (the volume of the metal in the thin metal wire 24)/(the volume ofthe thin metal wire 24 with a binder and/or a void)=M/(H×d)×100 [%]. Theterm “the thin metal wire 24” means a layer of the metal connectedcontinuously, independent from undercoat layers and overcoat layers. Theaverage thickness H is an average value measured by observing the crosssection in a region of 1 mm or more in total. As the metal volumecontent is increased, the volume resistance is reduced advantageously.However, in a case where the metal volume content is excessivelyincreased, the metallic reflection cannot be sufficiently prevented evenwhen the surface shape is optimized. Therefore, the metal volume contentis preferably 35% or more, more preferably 50% or more, furtherpreferably 50% to 80%, particularly preferably 55% to 65%. The metalvolume content of the thin metal wire may be changed in the thicknessdirection. It is preferred that the metal volume content is lower in thevicinity of the surface than in the center of the thin metal wire.

In general, a conventional thin metal wire 24 has a luster surface.Therefore, as shown in FIG. 2A, the surface intensely reflects a visiblelight, and the ratio of the specularly reflected light to all thereflected lights (specular reflectance) is increased. As a result, thethin metal wire 24 is highly visible disadvantageously. In addition, asshown in FIG. 3A, in a case where the thin metal wire 24 has a low metalvolume content, though the incident light is introduced into spacesbetween metal particles to lower the specular reflectance, the metalparticles exhibit a loose connection, thereby resulting in a highelectrical resistance or a poor wiring adhesion disadvantageously. Theelectrical resistance of the electrode portion 18 can be lowered byperforming a calender treatment or the like to increase the metal volumecontent. However, as shown in FIG. 3B, the metal particles are denselyarranged on the surface, whereby the specular reflectance issignificantly increased and the thin metal wire 24 is made highlyvisible disadvantageously. Thus, it is difficult to achieve both anappropriate visibility (the thin metal wire 24 being less visible) and alow resistance.

In contrast, in this embodiment, the electrode portion 18 has thesurface shape satisfying the condition of Ra²/Sm>0.01 μm. Therefore, asshown in FIG. 2B, the ratio of the scattered lights is increased and thespecular reflectance is lowered, whereby the thin metal wire 24 is lessvisible. Thus, even when the metal volume content is increased to 35% ormore, the light reflection from the electrode portion 18 can be reduced.Consequently, both of the appropriate visibility (the thin metal wire 24being less visible) and the low resistance can be achieved.

In this embodiment, it is preferred that at least the electrode portion18 has Sm of 4 μm or less. FIG. 4 is a graph plotting a specularreflectance change with respect to Ra²/Sm of the electrode portion 18.In a case where the electrode portion 18 has a surface shape satisfyingthe condition of Ra²/Sm>0.01 μm and has Sm of 4 μm or less, the specularreflectance can be reduced to 1.2% or less.

In this embodiment, it is preferred that the electrode portion 18 has adifference of less than 3% between the specular reflectances of thefront surface and the back surface. The difference is more preferablyless than 1%, further preferably less than 0.5%. The transparentsubstrate 12 has the surface having the electrode portion 18 and theopposite surface, and the back surface of the electrode portion 18 isthe surface that can be observed from the opposite surface side throughthe transparent substrate 12. The specular reflectances are determinedby subtracting the reflectance at the interface between air and thetransparent substrate 12.

This is effective, for example, in a case where metal wiring portions (afirst metal wiring portion 14A and a second metal wiring portion 14B)are formed on the front and back surfaces of one transparent substrate12 as shown in FIG. 5A.

In the transparent conductive film 10, the front surface of a firstelectrode portion 18A and the back surface of a second electrode portion18B, which is observed through the transparent substrate 12, have aspecular reflectance difference of less than 3%. Therefore, the thinmetal wire 24 in the first electrode portion 18A is less visible, andalso the thin metal wire 24 in the second electrode portion 18B is lessvisible. Consequently, even in a case where the metal wiring portion isformed on each of the front and back surfaces of one transparentsubstrate 12, the transparent conductive film can have an improvedvisibility, and the first electrode portion 18A and the second electrodeportion 18B can have a low resistance.

As shown in FIG. 5B, two transparent conductive films (a firsttransparent conductive film 10A and a second transparent conductive film10B) may be stacked. This structure is preferred because both of thefront surface of the first electrode portion 18A in the firsttransparent conductive film 10A and the front surface of the secondelectrode portion 18B in the second transparent conductive film 10B canexhibit a low specular reflectance. Thus, even in a case where the firsttransparent conductive film 10A and the second transparent conductivefilm 10B are stacked, the transparent conductive film can have animproved visibility, and the first electrode portion 18A and the secondelectrode portion 18B can have a low resistance.

A representative method for producing the transparent conductive film 10shown in FIGS. 1A and 1B will be briefly described below.

The transparent conductive film 10 may be produced as follows. Forexample, a photosensitive material having the transparent substrate 12and thereon a photosensitive silver halide-containing emulsion layer maybe exposed and developed, whereby metallic silver portions andlight-transmitting portions may be formed in the exposed areas and theunexposed areas respectively to obtain the metal wiring portion 14. Themetallic silver portions may be subjected to a physical developmenttreatment and/or a plating treatment to deposit a conductive metalthereon. The entire layer containing the metallic silver portions andthe conductive metal deposited thereon is referred to as the conductivemetal portion.

Alternatively, a photosensitive base layer to be plated containing apre-plating treatment material may be formed on the transparentsubstrate 12. The resultant layer may be exposed and developed, and maybe subjected to a plating treatment, whereby metal portions andlight-transmitting portions may be formed in the exposed areas and theunexposed areas respectively to form the metal wiring portion 14. Themetal portions may be further subjected to a physical developmenttreatment and/or a plating treatment to deposit a conductive metalthereon.

The following two processes can be preferably used in the method usingthe pre-plating treatment material. The processes are disclosed morespecifically in Japanese Laid-Open Patent Publication Nos. 2003-213437,2006-064923, 2006-058797, and 2006-135271, etc.

(a) A process comprising applying, to the transparent substrate 12, abase layer to be plated having a functional group interactable with aplating catalyst or a precursor thereof, exposing and developing thelayer, and subjecting the developed layer to a plating treatment to forma metal portion on the base material.

(b) A process comprising applying, to the transparent substrate 12, anunderlayer containing a polymer and a metal oxide and a base layer to beplated having a functional group interactable with a plating catalyst ora precursor thereof in this order, exposing and developing the layers,and subjecting the developed layers to a plating treatment to form ametal portion on the base material.

Alternatively, a photoresist film on a copper foil disposed on thetransparent substrate 12 may be exposed and developed to form a resistpattern, and the copper foil exposed from the resist pattern may beetched to form the metal wiring portion 14.

Alternatively, a paste containing fine metal particles may be printed onthe transparent substrate 12 to form the metal wiring portion 14.

Alternatively, a metal film may be vapor-deposited on the transparentsubstrate 12, a photoresist film may be formed on the metal film, thephotoresist film may be exposed and developed to form a mask pattern,and the metal film exposed from the mask pattern may be etched to formthe metal wiring portion 14.

Alternatively, the metal wiring portion 14 may be printed on thetransparent substrate 12 by using a screen or gravure printing plate.

Alternatively, the metal wiring portion 14 may be formed on thetransparent substrate 12 by using an inkjet method.

A method, which contains using a photographic photosensitive silverhalide material for producing the transparent conductive film 10 of thisembodiment, will be mainly described below.

The method using the photographic photosensitive silver halide materialfor producing the transparent conductive film 10 includes the followingthree processes different in the photosensitive materials anddevelopment treatments.

(1) A process comprising subjecting a photosensitive black-and-whitesilver halide material free of physical development nuclei to a chemicalor thermal development to form the metallic silver portions on thephotosensitive material.

(2) A process comprising subjecting a photosensitive black-and-whitesilver halide material having a silver halide emulsion layer containingphysical development nuclei to a solution physical development to formthe metallic silver portions on the material.

(3) A process comprising subjecting a stack of a photosensitiveblack-and-white silver halide material free of physical developmentnuclei and an image-receiving sheet having a non-photosensitive layercontaining physical development nuclei to a diffusion transferdevelopment to form the metallic silver portions on thenon-photosensitive image-receiving sheet.

In the process of (1), an integral black-and-white development procedureis used to form a transmittable conductive film such as alight-transmitting conductive film on the photosensitive material. Theresulting silver is a chemically or thermally developed silver in thestate of a high-specific surface area filament, and thereby shows a highactivity in the following plating or physical development treatment.

In the process of (2), the silver halide particles are melted around anddeposited on the physical development nuclei in the exposed areas toform a transmittable conductive film such as a light-transmittingconductive film on the photosensitive material. Also in this process, anintegral black-and-white development procedure is used. Though highactivity can be achieved since the silver halide is deposited on thephysical development nuclei in the development, the developed silver hasa spherical shape with small specific surface.

In the process of (3), the silver halide particles are melted in theunexposed areas, and are diffused and deposited on the developmentnuclei in the image-receiving sheet, to form a transmittable conductivefilm such as a light-transmitting conductive film on the sheet. In thisprocess, a so-called separate-type procedure is used, theimage-receiving sheet being peeled off from the photosensitive material.

A negative or reversal development treatment can be used in theprocesses. In the diffusion transfer development, the negativedevelopment treatment can be carried out using an auto-positivephotosensitive material.

The chemical development, thermal development, solution physicaldevelopment, and diffusion transfer development have the meaningsgenerally known in the art, and are explained in common photographicchemistry texts such as Shin-ichi Kikuchi, “Shashin Kagaku (PhotographicChemistry)”, Kyoritsu Shuppan Co., Ltd., 1955 and C. E. K. Mees, “TheTheory of Photographic Processes, 4th ed.”, Mcmillan, 1977. A liquidtreatment is generally used in the present invention, and also a thermaldevelopment treatment can be utilized. For example, techniques describedin Japanese Laid-Open Patent Publication Nos. 2004-184693, 2004-334077,and 2005-010752 and Japanese Patent Application Nos. 2004-244080 and2004-085655 can be used in the present invention.

The structure of each layer in the transparent conductive film 10 ofthis embodiment will be described in detail below.

<Support (Transparent Substrate 12)>

The support is not limited as long as it can support conductive portionsto be hereinafter described. The support is preferably a transparentsupport, and particularly preferably a plastic film. In the case ofusing the transparent support, the transparent conductive film of thepresent invention can be suitably used as a transparent conductivesheet.

Specifically, for example, the support is preferably a film of a plastichaving a melting point of about 290° C. or lower such as a PET (258°C.), polycycloolefin (134° C.), polycarbonate (250° C.), acrylicmaterial (128° C.), PEN (269° C.), PE (135° C.), PP (163° C.),polystyrene (230° C.), polyvinyl chloride (180° C.), polyvinylidenechloride (212° C.), or TAC (290° C.). The PET, polycycloolefin, andpolycarbonate are particularly preferred. The numerals in parenthesesrepresent the melting points. The support preferably has a visible lighttransmittance of 85% to 100% (according to JIS R 3106: 1998).

The thickness of the support is not particularly limited. In general,the thickness of the support may be arbitrarily selected within a rangeof 25 to 500 μm in view of use in the touch panel, theelectromagnetic-shielding film, or the like. In a case where the supportacts as a supporting member and a touch surface, the support may have athickness of more than 500 μm.

In a preferred embodiment, the support is subjected to at least onetreatment selected from the group consisting of atmospheric-pressureplasma treatments, corona discharge treatments, and ultravioletirradiation treatments beforehand. In such a treatment, a hydrophilicgroup such as an OH group is introduced to a surface of the treatedsupport to improve the adhesion of the conductive portion to behereinafter described. Among the above treatments, theatmospheric-pressure plasma treatment is preferred from the viewpoint offurther improving the adhesion of the conductive portion.

(Binder Portion)

A binder portion is a layer formed at least inside the thin metal wire24. In a more preferred embodiment, the support surface having the thinmetal wire 24 is preferably covered with the thin metal wire 24 and thebinder portion. The binder portion preferably contains a macromoleculedifferent from gelatins. The definition of the macromolecule differentfrom the gelatins will be described hereinbelow.

It is preferred that the binder portion is substantially free from thegelatins. The term “substantially free from the gelatins” means that thecontent of the gelatins in the binder portion is less than 0.002 mg/cm².The gelatin content is preferably 0.001 mg/cm² or less, more preferably0.0005 mg/cm² or less, in view of preventing ion migration. The lowerlimit of the gelatin content is not particularly restricted, and ispreferably 0 mg/cm². The gelatin content in the binder portion is theamount of the gelatins contained in a unit area (m²) of a planprojection view, which is obtained by projecting in a directionperpendicular to the surface of the binder portion.

The thickness of the binder portion is not particularly limited, and isgenerally smaller than the thickness of a conductive thin wire portion.The binder portion may contain a component other than the macromoleculedifferent from the gelatins.

The macromolecule different from the gelatins (hereinafter referred tosimply as the macromolecule) is preferably free from proteins. In otherwords, it is preferred that the macromolecule is not decomposed by aproteolytic enzyme.

More specifically, for example, the binder portion may contain at leastone resin selected from the group consisting of acrylic resins, styreneresins, vinyl resins, polyolefin resins, polyester resins, polyurethaneresins, polyamide resins, polycarbonate resins, polydiene resins, epoxyresins, silicone resins, cellulose-type polymers, and chitosan-typepolymers, and may contain a copolymer of monomers for such resins. Amongthem, the binder portion may contain at least one resin selected fromthe group consisting of the acrylic resins, styrene resins, andpolyester resins or a copolymer of monomers usable for those resins.

In particular, in a preferred embodiment, the macromolecule may be apolymer (copolymer) represented by the following general formula (1) tofurther prevent water ingress.-(A)_(x)-(B)_(y)—(C)_(z)-(D)_(w)-  General formula (1):

In the general formula (1), (A), (B), (C), and (D) represent thefollowing repeating units respectively.

R¹ is a methyl group or a halogen atom, preferably a methyl group, achlorine atom, or a bromine atom. p is an integer of 0 to 2, preferably0 or 1, more preferably 0.

R² is a methyl group or an ethyl group, preferably a methyl group. R³ isa hydrogen atom or a methyl group, preferably a hydrogen atom. L is adivalent linking group, preferably a group represented by the followinggeneral formula (2).—(CO—X¹)_(r)—X²—  General formula (2):

In the general formula (2), X¹ is an oxygen atom or —NR³⁰—. R³⁰ is ahydrogen atom, an alkyl group, an aryl group, or an acyl group, and thegroups may have a substituent (such as a halogen atom, a nitro group, ora hydroxyl group). R³⁰ is preferably a hydrogen atom, an alkyl grouphaving 1 to 10 carbon atoms (such as a methyl group, an ethyl group, ann-butyl group, or an n-octyl group), or an acyl group (such as an acetylgroup or a benzoyl group). X¹ is particularly preferably an oxygen atomor —NH—.

X² is an alkylene group, an arylene group, an alkylene-arylene group, anarylene-alkylene group, or an alkylene-arylene-alkylene group, and —O—,—S—, —OCO—, —CO—, —COO—, —NH—, —SO₂—, —N(R³¹)—, —N(R³¹)SO₂—, or the likemay be inserted into these groups. R³¹ is a linear or branched alkylgroup having 1 to 6 carbon atoms such as a methyl group, an ethyl group,or an isopropyl group. Preferred examples of X² include a dimethylenegroup, a trimethylene group, a tetramethylene group, an o-phenylenegroup, a m-phenylene group, a p-phenylene group, —CH₂CH₂OCOCH₂CH₂—, and—CH₂CH₂OCO(C₆H₄)—.

r is 0 or 1.

q is 0 or 1, preferably 0.

R⁴ is an alkyl, alkenyl, or alkynyl group having 5 to 80 carbon atoms,preferably an alkyl group having 5 to 50 carbon atoms, more preferablyan alkyl group having 5 to 30 carbon atoms, further preferably an alkylgroup having 5 to 20 carbon atoms.

R⁵ is a hydrogen atom, a methyl group, an ethyl group, a halogen atom,or —CH₂COOR⁶, preferably a hydrogen atom, a methyl group, a halogenatom, or —CH₂COOR⁶, more preferably a hydrogen atom, a methyl group, or—CH₂COOR⁶, particularly preferably a hydrogen atom.

R⁶ is a hydrogen atom or an alkyl group having 1 to 80 carbon atoms, andmay be the same as or different from R⁴. The carbon number of R⁶ ispreferably 1 to 70, more preferably 1 to 60.

In the general formula (1), x, y, z, and w represents the molar ratiosof the repeating units.

x is 3 to 60 mol %, preferably 3 to 50 mol %, more preferably 3 to 40mol %.

y is 30 to 96 mol %, preferably 35 to 95 mol %, and particularlypreferably 40 to 90 mol %.

In a case where z is excessively low, the polymer exhibits a lowaffinity for a hydrophilic protective colloid such as a gelatin, wherebygeneration of an aggregation or peeling defect of a matting agent isincreased. In a case where z is excessively high, the matting agent isdisadvantageously dissolved in an alkaline processing liquid for aphotosensitive material. Therefore, z is 0.5 to 25 mol %, preferably 0.5to 20 mol %, and particularly preferably 1 to 20 mol %.

w is 0.5 to 40 mol %, preferably 0.5 to 30 mol %.

In the general formula (1), it is particularly preferred that x is 3 to40 mol %, y is 40 to 90 mol %, z is 0.5 to 20 mol %, and w is 0.5 to 10mol %.

The polymer represented by the general formula (1) is preferably apolymer represented by the following general formula (3).

In the general formula (3), x, y, z, and w have the same meanings asabove.

The polymer represented by general formula (1) may contain a repeatingunit other than those of (A), (B), (C), and (D) above. Examples ofmonomers for forming the other repeating units include acrylic acidesters, methacrylic acid esters, vinyl esters, olefins, crotonic acidesters, itaconic acid diesters, maleic acid diesters, fumaric aciddiesters, acrylamide-based compounds, unsaturated carboxylic acids,allyl compounds, vinyl ethers, vinyl ketones, heterocyclic vinylcompounds, glycidyl esters, and unsaturated nitriles. Such monomers aredescribed also in [0010] to [0022] of Japanese Patent No. 3754745.

From the viewpoint of hydrophobicity, the monomer is preferably anacrylic acid ester or a methacrylic acid ester, more preferably ahydroxyalkyl methacrylate or acrylate such as hydroxyethyl methacrylate.The polymer represented by general formula (1) preferably contains arepeating unit represented by the general formula (E) in addition to therepeating units of the formulae (A), (B), (C), and (D).

In the general formula (E), L_(E) is an alkylene group, preferably analkylene group having 1 to 10 carbon atoms, more preferably an alkylenegroup having 2 to 6 carbon atoms, further preferably an alkylene grouphaving 2 to 4 carbon atoms.

The polymer represented by general formula (1) is particularlypreferably a polymer represented by the following general formula (4).

In the general formula (4), a1, b1, c1, d1, and e1 represents the molarratios of the monomer units. a1 is 3 to 60 (mol %), b1 is 30 to 95 (mol%), c1 is 0.5 to 25 (mol %), d1 is 0.5 to 40 (mol %), and e1 is 1 to 10(mol %).

The preferred range of a1 is the same as that of x, the preferred rangeof b1 is the same as that of y, the preferred range of c1 is the same asthat of z, and the preferred range of d1 is the same as that of w.

e1 is 1 to 10 mol %, preferably 2 to 9 mol %, more preferably 2 to 8 mol%.

Specific examples of the polymer represented by general formula (1) areshown below without intention of restricting the present inventionthereto.

The weight-average molecular weight of the polymer represented bygeneral formula (1) is preferably 1,000 to 1,000,000, more preferably2,000 to 750,000, further preferably 3,000 to 500,000.

The polymer represented by general formula (1) may be synthesizedaccording to Japanese Patent Nos. 3305459 and 3754745, etc.

<Solvent>

The solvent used for forming the silver salt emulsion layer is notparticularly limited, and examples thereof include water, organicsolvents (e.g. alcohols such as methanol, ketones such as acetone,amides such as formamide, sulfoxides such as dimethyl sulfoxide, esterssuch as ethyl acetate, ethers), ionic liquids, and mixtures thereof.

<Other Additives>

The additives used in this embodiment are not particularly limited, andmay be preferably selected from known additives.

[Other Layers]

A protective layer (not shown) may be formed on the silver salt emulsionlayer. In addition, an undercoat layer or the like may be formed belowthe silver salt emulsion layer.

The steps for producing the transparent conductive film 10 will bedescribed below.

[Exposure]

In this embodiment, the mesh pattern 28 may be formed in a printingprocess, and may be formed by exposure and development treatments, etc.in another process. Thus, a photosensitive material having thetransparent substrate 12 and thereon the silver salt-containing layer ora photosensitive material coated with a photopolymer forphotolithography is subjected to the exposure treatment. Anelectromagnetic wave may be used in the exposure. For example, theelectromagnetic wave may be a light such as a visible light or anultraviolet light, or a radiation ray such as an X-ray. The exposure maybe carried out using a light source having a wavelength distribution ora specific wavelength.

[Development Treatment]

In this embodiment, the emulsion layer is subjected to the developmenttreatment after the exposure. Common development treatment technologiesfor photographic silver salt sheets, photographic papers, printengraving sheets, emulsion masks for photomasking, and the like may beused in the present invention.

In the present invention, the development process may include a fixationtreatment for removing the silver salt in the unexposed areas tostabilize the material. Fixation treatment technologies for photographicsilver salt sheets, photographic papers, print engraving sheets,emulsion masks for photomasking, and the like may be used in the presentinvention. The developed and fixed photosensitive material is preferablysubjected to a water washing treatment or a stabilization treatment.

The ratio of the metallic silver portions contained in the exposed areasafter the development to the silver contained in the areas before theexposure is preferably 50% or more, more preferably 80% or more by mass.In a case where the ratio is 50% or more by mass, a high conductivitycan be achieved.

The transparent conductive film 10 can be obtained by the above steps.The surface resistance of the resultant transparent conductive film 10is preferably 0.1 to 300 ohm/sq. Preferred surface resistance ranges ofthe transparent conductive film 10 depend on the use of the transparentconductive film 10. In the case of using the transparent conductive film10 in the electromagnetic-shielding material, the surface resistance ispreferably 10 ohm/sq or less, more preferably 0.1 to 3 ohm/sq. In thecase of using the transparent conductive film 10 in the touch panel, thesurface resistance is preferably 1 to 70 ohm/sq, more preferably 5 to 50ohm/sq, further preferably 5 to 30 ohm/sq. The transparent conductivefilm 10 may be subjected to a calender treatment after the developmenttreatment to obtain a desired surface resistance.

[Physical Development Treatment and Plating Treatment]

In this embodiment, to increase the conductivity of the metallic silverportion formed by the above exposure and development treatments,conductive metal particles may be deposited thereon by a physicaldevelopment treatment and/or a plating treatment. In this embodiment,the conductive metal particles may be deposited on the metallic silverportion by only one of the physical development and plating treatmentsor by the combination of the treatments. The metallic silver portion,subjected to the physical development treatment and/or the platingtreatment in this manner, is also referred to as the conductive metalportion.

In this embodiment, the physical development is such a process thatmetal ions such as silver ions are reduced by a reducing agent, wherebymetal particles are deposited on a metal or metal compound core. Suchphysical development has been used in the fields of instant B & W film,instant slide film, printing plate production, etc., and thetechnologies can be used in the present invention. The physicaldevelopment may be carried out at the same time as the above developmenttreatment after the exposure, and may be carried out after thedevelopment treatment separately.

In this embodiment, the plating treatment may contain electrolessplating (such as chemical reduction plating or displacement plating),electrolytic plating, or a combination thereof. Known electrolessplating technologies for printed circuit boards, etc. may be used inthis embodiment. The electroless plating is preferably electrolesscopper plating.

[Oxidation Treatment]

In this embodiment, the metallic silver portion formed by thedevelopment treatment or the conductive metal portion formed by thephysical development treatment and/or the plating treatment ispreferably subjected to an oxidation treatment. For example, by theoxidation treatment, a small amount of a metal deposited on thelight-transmitting portion can be removed, so that the transmittance ofthe light-transmitting portion can be increased to approximately 100%.

[Conductive Metal Portion]

In this embodiment, the line width of the conductive metal portion (theline width Wb of the thin metal wire 24) may be selected within a rangeof 30 μm or less. In the case of using the transparent conductive film10 as the electromagnetic-shielding film, the line width of the thinmetal wire 24 is preferably 1 to 20 μm, more preferably 1 to 9 μm,further preferably 2 to 7 μm. In the case of using the transparentconductive film 10 as the conductive film in the touch panel, the lowerlimit of the line width is preferably 1 μm or more, 3 μm or more, 4 μmor more, or 5 μm or more, and the upper limit thereof is preferably 15μm or less, 10 μm or less, 9 μm or less, or 8 μm or less. In a casewhere the line width Wb is less than the lower limit, the conductivemetal portion has an insufficient conductivity, whereby the touch panelusing the conductive metal portion has insufficient detectionsensitivity. On the other hand, in a case where the line width is morethan the upper limit, moire is significantly generated due to theconductive metal portion, and the touch panel using the conductive metalportion has a poor visibility. On the condition that the line width iswithin the above range, the moire of the conductive metal portion isimproved, and the visibility is remarkably improved. The thin wire pitch(the arrangement pitch of the thin metal wire 24) is preferably 100 to400 μm, further preferably 150 to 300 μm, most preferably 210 to 250 μm.The metal wiring 20 in the wiring portion 22 may have a part with a linewidth of more than 200 μm for the purpose of ground connection, etc.

In this embodiment, the opening ratio of the conductive metal portion ispreferably 85% or more, more preferably 90% or more, most preferably 95%or more, in view of the visible light transmittance. The opening ratiois the ratio of the light-transmitting portions other than the thinmetal wire 24 to the entire conductive metal portion. For example, asquare lattice pattern having a line width of 6 μm and a thin wire pitchof 240 μm has an opening ratio of 95%.

[Light-Transmitting Portion]

In this embodiment, the light-transmitting portion is a portion having alight transmittance, other than the conductive metal portions in thetransparent conductive film 10. The visible light transmittance of thelight-transmitting portion is 80% or more, preferably 90% or more, morepreferably 95% or more, further preferably 97% or more, most preferably98% or more.

The exposure is preferably carried out using a glass mask method or alaser lithography pattern exposure method.

[Transparent Conductive Film 10]

In the transparent conductive film 10 of this embodiment, the thicknessof the transparent substrate 12 is preferably 5 to 350 μm, morepreferably 30 to 150 μm. On the condition that the thickness is withinthe range of 5 to 350 μm, a desired visible light transmittance can beobtained, and the transparent substrate 12 can be easily handled.

The thickness of the metallic silver portion formed on the transparentsubstrate 12 may be appropriately selected by controlling the thicknessof the coating liquid for the silver salt-containing layer applied tothe transparent substrate 12. The thickness of the metallic silverportion may be selected within a range of 0.001 μm to 0.2 mm, and ispreferably 30 μm or less, more preferably 20 μm or less, furtherpreferably 0.01 to 9 μm, most preferably 0.05 to 5 μm. The metallicsilver portion is preferably formed in a patterned shape. The metallicsilver portion may have a monolayer structure or a multilayer structurecontaining two or more layers. In a case where the metallic silverportion has a patterned multilayer structure containing two or morelayers, the layers may have different wavelength color sensitivities. Inthis case, different patterns can be formed in the layers by usingexposure lights with different wavelengths.

In the case of using the transparent conductive film 10 in the touchpanel, the conductive metal portion preferably has a smaller thickness.As the thickness is reduced, the viewing angle and visibility of thedisplay panel 16 a are improved. Thus, the thickness of the layer of theconductive metal on the conductive metal portion is preferably smallerthan 9 μm, more preferably 0.1 μm or more but smaller than 5 μm, furtherpreferably 0.1 μm or more but smaller than 3 μm.

In this embodiment, the metallic silver portion can be formed with adesired thickness by controlling the coating thickness of the silversalt-containing layer, and the thickness of the layer of the conductivemetal particles can be controlled in the physical development treatmentand/or the plating treatment, whereby the transparent conductive film 10having a thickness of smaller than 5 μm (preferably less than 3 μm) canbe easily produced.

The plating or the like is not necessarily carried out in the method forproducing the transparent conductive film 10 of this embodiment. This isbecause the desired surface resistance can be obtained by controllingthe applied silver amount and the silver/binder volume ratio of thesilver salt emulsion layer in the method for producing the transparentconductive film 10 of this embodiment.

[Debindering Treatment]

The debindering treatment is a process of treating the support (thetransparent substrate 12) having the conductive portion (at least theelectrode portion 18) with a proteolytic enzyme, an oxidizing agent suchas an oxo acid, or the like, for decomposing a water-soluble binder suchas a gelatin. In this process, the water-soluble binder such as thegelatin is decomposed and removed from the exposed and developedphotosensitive layer to further prevent the ion migration in the thinmetal wire 24.

Substances for use in this process will be described in detail, and thenthe procedures of this process will be described in detail below.

(Proteolytic Enzyme)

The proteolytic enzyme (hereinafter referred to also as the enzyme) maybe a known plant or animal enzyme capable of hydrolyzing a protein suchas the gelatin. For example, the proteolytic enzyme may be a pepsin,rennin, trypsin, chymotrypsin, cathepsin, papain, ficin, thrombin,renin, collagenase, bromelain, bacterial protease, or the like. Theproteolytic enzyme is particularly preferably the trypsin, papain,ficin, or bacterial protease. In particular, the bacterial protease iseasily available, and for example, Bioprase manufactured by Nagase &Co., Ltd. is known as an inexpensive commercial product.

(Oxidizing Agent)

The oxidizing agent may be a known agent capable of oxidativelydecomposing the protein such as the gelatin. For example, the oxidizingagent may be a salt of a halogen and an oxo acid, such as ahypochlorite, chlorite, or chlorate. In particular, sodium hypochloriteis inexpensive and commercially-available with ease.

(Reduction Treatment)

In the case of using the oxidizing agent for decomposing the gelatin,the metal in the thin metal wire 24 may be oxidized to increase theelectrical resistance. Therefore, it is preferred that a reductiontreatment is carried out in combination with the oxidizing agenttreatment. The type of an aqueous reducing solution used for thereduction treatment is not particularly limited as long as reduction ofsilver can be reduced by the solution. For example, the aqueous reducingsolution may be an aqueous solution of sodium sulfite, hydroquinone,p-phenylenediamine, oxalic acid, ascorbic acid, sodium borohydride, orthe like. It is further preferred that the aqueous solution has pH of 10or more.

The treatment method is not particularly limited, and the support havingthe conductive portion may be brought into contact with the aqueousreducing solution. For example, the support may be immersed in theaqueous reducing solution to achieve the contact.

The conductivity can be further increased by the reduction treatment.Therefore, the reduction treatment may be preferably carried out even ina case where the gelatin decomposition with the oxidizing agent is notcarried out.

(Process Procedure)

The procedure of the debindering treatment process is not particularlylimited as long as the support having the conductive portion can bebrought into contact with the enzyme or the oxidizing agent. Inparticular, the procedure is not particularly limited as long as theconductive and non-conductive portions on the support can be broughtinto contact with the enzyme. In general, the support having theconductive portion may be brought into contact with a treatment liquidcontaining the enzyme (an enzyme liquid). For example, to achieve thecontact, the treatment liquid may be applied to the support having theconductive portion, or alternatively the support having the conductiveportion may be immersed in the treatment liquid.

The enzyme content of the treatment liquid is not particularly limited,and may be appropriately selected depending on the ability and desiredperformance of the enzyme used. The ratio of the enzyme to the total ofthe treatment liquid is preferably about 0.05% to 20% by mass, morepreferably 5% to 10% by mass, to easily control the degree of thedecomposition and removal of the gelatin.

The treatment liquid may contain, in addition to the enzyme, a pHbuffer, an antibacterial compound, a wetting agent, a preservative, etc.if necessary.

The pH of the treatment liquid is selected by an experiment formaximizing the activity of the enzyme. In general, the pH is preferably5 to 7. Also the temperature of the treatment liquid is preferably atemperature suitable for increasing the activity of the enzyme, and maybe 25° C. to 45° C. specifically.

The contact time is not particularly limited, and is preferably 10 to500 seconds, more preferably 90 to 360 seconds, in which the conductiveportion exhibits more excellent ion migration prevention.

After the treatment with the treatment liquid, the support having theconductive portion may be washed with a warm water if necessary. In thisprocess, residues of the decomposed gelatin, the proteolytic enzyme, theoxidizing agent, and the like can be removed to further prevent the ionmigration.

The washing method is not particularly limited as long as the supporthaving the conductive portion can be brought into contact with the warmwater. For example, the support having the conductive portion may beimmersed in the warm water, or alternatively the warm water may beapplied onto the support having the conductive portion.

The optimum temperature of the warm water may be appropriately selecteddepending on the type of the proteolytic enzyme used. The temperature ispreferably 20° C. to 80° C., more preferably 40° C. to 60° C., in viewof productivity.

The contact time (washing time) of the warm water and the support havingthe conductive portion is not particularly limited. The contact time ispreferably 1 to 600 seconds, more preferably 30 to 360 seconds, in viewof productivity.

[Calender Treatment]

After the development treatment or the gelatin removal treatment, thethin metal wire 24 is smoothened by a calender treatment. The calendertreatment may be carried out in a case where the metal wiring portion 14is formed on the transparent substrate 12 by using the photographicphotosensitive silver halide material. In addition, the calendertreatment may be carried out in the following cases:

(a) a case where the metal wiring portion 14 is formed on thetransparent substrate 12 by the plating treatment;

(b) a case where the metal wiring portion 14 is formed by selectivelyetching the copper foil on the transparent substrate 12;

(c) a case where the metal wiring portion 14 is formed by printing thepaste containing the fine metal particles on the transparent substrate12;

(d) a case where the metal wiring portion 14 is formed byvapor-depositing the metal film on the transparent substrate 12 and thenselectively etching the metal film;

(e) a case where the metal wiring portion 14 is formed by printing usingthe screen or gravure printing plate on the transparent substrate 12;and

(f) a case where the metal wiring portion 14 is formed on thetransparent substrate 12 by using the inkjet method.

In particular, the calender treatment is effective in a case where thesurface 12 a of the transparent substrate 12 (the surface on which themetal wiring portion 14 is formed) is a flat surface. The metal volumecontent of the metal wiring portion 14 is increased to significantlyincrease the conductivity by the calender treatment. In the case ofperforming the above debindering treatment, substances inhibiting themetal connection are reduced, whereby the conductivity increase effectof the calender treatment is enhanced.

Examples of such calender treatments include a first method shown inFIG. 6A and a second method shown in FIG. 6B.

As shown in FIG. 6A, a mat member 32 having a concave-convex surface 30and a pair of calender rollers arranged facing each other (a firstcalender roller 34A and a second calender roller 34B) are used in thefirst method. A metal plate 32A or a resin film 32B may be used as themat member 32. Examples of such metal plates 32A include chromium-platedstainless plates and nitride iron plates, and examples of such resinfilms 32B include PET (polyethylene terephthalate) films. In particular,the resin film 32B is preferably used because the resin film 32B can beconveyed in the form of a roll together with a roll of the transparentconductive film 10 to achieve a high productivity. A metal roller or aresin roller is used as each of the first calender roller 34A and thesecond calender roller 34B. The resin roller contains an epoxy,polyimide, polyamide, polyimideamide, etc. The metal roller and theresin roller may be used in combination. At least one of the firstcalender roller 34A and the second calender roller 34B may have a crownshape, the diameter of the roller center being larger than the diametersof the roller ends.

The transparent conductive film 10 is placed on the surface 30 (theconcave-convex surface) of the mat member 32. In this step, thetransparent conductive film 10 is placed on the surface 30 of the matmember 32 to obtain one stack 36 in such a manner that the electrodeportion 18 in the transparent conductive film 10 faces the surface 30 ofthe mat member 32. The stack 36 is interposed between the first calenderroller 34A and the second calender roller 34B arranged facing eachother. The first calender roller 34A and the second calender roller 34Bare rotated, the first calender roller 34A is brought into contact withthe transparent substrate 12 in the transparent conductive film 10, thesecond calender roller 34B is brought into contact with the mat member32, and the transparent conductive film 10 is pressure-treated whilebeing conveyed in one direction.

As shown in FIG. 6B, a roller having a roughened surface is used as atleast one of the first calender roller 34A and the second calenderroller 34B without using the mat member 32 in the second method. In thisexample, a surface 38 of the first calender roller 34A, with which theelectrode portion 18 of the transparent conductive film 10 is broughtinto contact, is roughened.

The transparent conductive film 10 is interposed between the firstcalender roller 34A and the second calender roller 34B arranged facingeach other, and the first calender roller 34A and the second calenderroller 34B are rotated. Then, the surface 38 of the first calenderroller 34A is brought into contact with the electrode portion 18 in thetransparent conductive film 10, and the second calender roller 34B isbrought into contact with the transparent substrate 12, whereby thetransparent conductive film 10 is pressure-treated while being conveyedin one direction.

In the second method, the transparent conductive film 10 can becontinuously calender-treated in the form of a roll, and the resin film32B is not wasted. Therefore, as compared with the first method, thesecond method is more preferred from the viewpoints of production rateand cost.

In the calender treatment, the lower limit of the line pressure ispreferably 1960 N/cm (200 kgf/cm, corresponding to a surface pressure of699.4 kgf/cm²) or more, further preferably 2940 N/cm (300 kgf/cm,corresponding to a surface pressure of 935.8 kgf/cm²) or more. The upperlimit of the line pressure is 6880 N/cm (700 kgf/cm) or less.

The calender treatment is preferably carried out at a temperature of 10°C. (without temperature control) to 100° C. Though the preferredtreatment temperature range depends on the density and shape of the meshpattern 28 of the thin metal wire 24 or the metal wirings 20 in thewiring portion 22, the type of the binder, etc., the temperature is morepreferably 10° C. (without temperature control) to 50° C. in general.

It is preferred that the concave-convex surface shapes of the mat member32 (the metal plate) used in the first method and the first calenderroller 34A (the metal roller) used in the second method have an Ra²/Smvalue of more than 0.015 μm.

Alternatively, it is preferred that the concave-convex surface shapes ofthe mat member 32 (the metal plate) used in the first method and thefirst calender roller 34A (the metal roller) used in the second methodhave an Sm value equal to or smaller than the line width Wb of the thinmetal wire 24, an Ra value equal to or smaller than ⅙ of the thicknessof the thin metal wire 24 measured before the calender treatment, and anRa²/Sm value of more than 0.015 μm.

FIG. 7 is a graph plotting specular reflectance changes with respect tothe Ra²/Sm value of the pressing surface of the metal roller in a casewhere the Sm value of the metal roller is equal to or smaller than theline width Wb of the thin metal wire 24 and in a case where the Sm valueof the metal roller is larger than the line width Wb of the thin metalwire 24, the line width Wb of the thin metal wire 24 being 5 μm. As isclear from FIG. 7, in the case where the Sm value of the metal roller isequal to or smaller than the line width Wb of the thin metal wire 24,though the specular reflectance is 3.8% at Ra²/Sm of 0.015 μm, thespecular reflectance can be reduced to less than 1% at Ra²/Sm of morethan 0.015 μm. Of course, even when the Sm value is larger than the linewidth Wb of the thin metal wire 24, the specular reflectance can bereduced more efficiently at Ra²/Sm of more than 0.015 μm than at Ra²/Smof 0.015 μm or less.

The operation, which varies depending on the relationships of the linewidth Wb and the thickness (the thickness tc before the calendertreatment) of the thin metal wire 24 and the Sm and Ra values of themetal plate 32A or the metal roller, will be described below withreference to FIGS. 8A to 8D.

As shown in FIG. 8A, in a case where the Sm value of the metal plate 32Aor the metal roller is equal to or smaller than the line width Wb of thethin metal wire 24, a convex portion 40 of the metal plate 32A or themetal roller is naturally brought into contact with the thin metal wire24. This is suitable for improving the visibility.

As shown in FIG. 8B, in a case where the Sm value of the metal plate 32Aor the metal roller is larger than the line width Wb of the thin metalwire 24, the probability of the contact between the convex portion 40 ofthe metal plate 32A or the metal roller and the thin metal wire 24 isdecreased. Furthermore, the convex portion 40 has a lower inclinationangle. Therefore, though breakage of the thin metal wire 24 is reduced,the visibility cannot be easily improved in some cases.

As shown in FIG. 8C, in a case where the Ra value of the metal plate 32Aor the metal roller is less than 0.15 μm, the effect of diffusing thespecularly reflected light is lowered due to the small irregularity.Therefore, the Ra value of the metal plate 32A or the metal roller ispreferably 0.15 μm or more.

As shown in FIG. 8D, in a case where the Ra value of the metal plate 32Aor the metal roller is larger than tc/5, in which tc is the thickness ofthe thin metal wire 24 measured before the calender treatment, theprobability of the breakage in the thin metal wire 24 is increased.Therefore, the Ra value of the metal plate 32A or the metal roller ispreferably equal to or smaller than tc/5, in which tc is the thicknessof the thin metal wire 24 measured before the calender treatment.

In the case of using the mat member 32 (the resin film 32B) in the firstmethod, the concave-convex surface shape of the resin film 32Bpreferably has an Ra value of more than 0.15 μm. Furthermore, theconcave-convex surface shape of the resin film 32B preferably has anRa²/Sm value of more than 0.01 μm. FIG. 9 is a graph plotting a specularreflectance change with respect to the Ra²/Sm value of the pressingsurface of the resin film 32B. As is clear from FIG. 9, though thespecular reflectance is 2.8% at Ra²/Sm of 0.01 μm in the pressingsurface of the resin film 32B, the specular reflectance can be reducedto less than 1% at Ra²/Sm of more than 0.01 μm.

Incidentally, because the concave-convex surface of the resin film 32Bis deformed, the resin film 32B cannot be used repeatedly. Nevertheless,because the deformed resin film 32B does not pass through the electrodeportion 18 (the thin metal wire 24) in the transparent conductive film10, the calender treatment can be performed without wire breakage unlikein the case of using the metal plate 32A or the metal roller. Thus, theRa range has no upper limit. However, in a case where the Ra value islarger than ¼ of the thickness tc of the thin metal wire 24 measuredbefore the calender treatment, the resistance lowering in the calendertreatment is reduced. Therefore, the Ra value is preferably equal to orsmaller than ¼ of the thickness tc of the thin metal wire 24 before thecalender treatment, more preferably equal to or smaller than ⅙ thereof.The Ra value of the resin film 32B is preferably 0.15 μm or more. In thecase where the Ra value is less than 0.15 μm, the light reflection maybe increased, and the pattern may become highly visible.

[Other Production Methods]

In addition to the above production method, a method of forming themetal wiring portion 14 on the transparent substrate 12 having aconcave-convex surface 12 a can be preferably used. In this case, in thesurface 12 a, only a portion corresponding to the electrode portion 18may have the concave-convex shape. Of course, the entire surface 12 amay have the concave-convex shape. Consequently, in the case where themetal wiring portion 14 is formed on the surface 12 a of the transparentsubstrate 12, the concave-convex shape of the surface 12 a of thetransparent substrate 12 is transferred to at least a surface of theelectrode portion 18.

The surface 12 a of the transparent substrate 12 preferably has a shapewith an Ra value of more than 0.15 μm. Furthermore, the surface 12 apreferably has an Ra²/Sm value of more than 0.01 μm. In this case, inthe resultant transparent conductive film, at least the electrodeportion 18 can have the surface shape satisfying the condition ofRa²/Sm>0.01 μm, and the metal volume content can be 35% or more.

The method using the plating treatment to form the metal wiring portion14 on the transparent substrate 12, the method containingvapor-depositing the metal film on the transparent substrate 12 andselectively etching the metal film to form the metal wiring portion 14,or the like can be preferably used for forming the metal wiring portion14 on the transparent substrate 12 having the concave-convex surface 12a. The methods are particularly preferred because it is capable offorming the metal wiring portion 14 with a high metal volume content.

[Silver Fusion Treatment]

(Light Irradiation Process)

After the development treatment and any one of the above-describedprocesses, a light irradiation process for irradiating the conductiveportion (at least the electrode portion 18) with a pulsed light from axenon flash lamp is preferably carried out. This process is capable oflowering the resistance of the conductive portion. The reason for theconductivity improvement in the transparent conductive film 10 is notclear, but it is presumed that the macromolecule and/or the gelatin areevaporated at least partially by heat under the irradiation with thepulsed light from the xenon flash lamp, whereby the metal (conductivesubstance) components are readily connected with each other.

The irradiation amount of the pulsed light is not particularly limited,and is preferably 1 to 1500 J, more preferably 100 to 1000 J, furtherpreferably 500 to 800 J, per 1 pulse. The irradiation amount can bemeasured using a common ultraviolet intensity meter such as anilluminance meter having a detection peak at 300 to 400 nm.

For example, in the case of using the transparent conductive film 10 asthe electrode for the touch panel, it is preferred that the thin metalwire 24 has a line width of 1 to 15 μm and a thickness of 1 to 3 μm, sothat the conductive portion is not visible to the naked eye. In the caseof using such line width and thickness, the conductive portion isirradiated with the pulsed light preferably 1 to 2000 times, morepreferably 1 to 50 times, further preferably 1 to 30 times.

(Heating Process)

After the development treatment and any one of the above-describedprocesses, a heating treatment process for heating the support (thetransparent substrate 12) having the conductive portion (at least theelectrode portion 18) is preferably carried out. By performing thisprocess, the transparent conductive film 10 can be obtained with animproved conductivity in the conductive portion, an excellent adhesionof the thin metal wire 24, and an ion migration inhibition ability.Furthermore, this process is capable of reducing the haze of thetransparent conductive film 10, improving the adhesion of the conductiveportion, improving a surface property in the oxidation treatment, orlowering the surface resistance.

The heating treatments include a treatment of contacting the supporthaving the conductive portion with a superheated vapor. The superheatedvapor may be a superheated water vapor or a mixture of a superheatedwater vapor and another gas.

It is preferred that the superheated vapor is in contact with theconductive portion within a supply time range of 10 to 70 seconds. Onthe condition that the supply time is 10 seconds or more, theconductivity is greatly improved. The conductivity improvement reaches asaturation point at a supply time of about 70 seconds. Therefore, thesupply time of more than 70 seconds is not preferred from the viewpointof economic efficiency. The supply amount of the superheated vapor to bebrought into contact with the conductive portion is preferably 500 to600 g/m³, and the temperature of the superheated vapor is preferablycontrolled within a range of 100° C. to 160° C. at 1 atm.

The heating treatment may be carried out at 80° C. to 150° C. Theheating time is not particularly limited, and is preferably 0.1 to 5.0hours, more preferably 0.5 to 1.0 hour, in view of achieving moreexcellent effect.

[Stabilization Treatment]

After the development treatment and any one of the above-describedprocesses, a process for bringing a migration inhibitor into contactwith the support having the conductive portion is preferably carriedout. By performing this process, the metallic silver in the conductiveportion is stabilized, the ion migration is sufficiently reduced, andthe reliability in a high-humidity and high-temperature environment isimproved.

The migration inhibitor for this process may be a known substance. Forexample, the migration inhibitor is preferably a nitrogen-containingheterocyclic compound or an organic mercapto compound, particularlypreferably a nitrogen-containing heterocyclic compound.

The nitrogen-containing heterocyclic compound is preferably a 5- or6-membered azole compound, particularly preferably a 5-membered azolecompound.

For example, the heterocycle may be a tetrazole ring, a triazole ring,an imidazole ring, a thiadiazole ring, an oxadiazole ring, aselenadiazole ring, an oxazole ring, a triazole ring, a benzoxazolering, a benzthiazole ring, a benzimidazole ring, a pyrimidine ring, atriazaindene ring, a tetraazaindene ring, a pentaazaindene ring, or thelike.

These rings may have a substituent. The substituent may be a nitrogroup, a halogen atom (such as a chlorine or bromine atom), a mercaptogroup, a cyano group, an alkyl group (such as a methyl, ethyl, propyl,t-butyl, or cyanoethyl group), an aryl group (such as a phenyl,4-methansulfonamidophenyl, 4-methylphenyl, 3,4-dichlorphenyl, ornaphthyl group), an alkenyl group (such as an allyl group), an aralkylgroup (such as a benzyl, 4-methylbenzyl, or phenethyl group), a sulfonylgroup (such as a methanesulfonyl, ethanesulfonyl, or p-toluenesulfonylgroup), a carbamoyl group (such as an unsubstituted carbamoyl,methylcarbamoyl, or phenylcarbamoyl group), a sulfamoyl group (such asan unsubstituted sulfamoyl, methylsulfamoyl, or phenylsulfamoyl group),a carbonamide group (such as an acetamide or benzamide group), asulfonamide group (such as a methanesulfonamide, benzenesulfonamide, orp-toluenesulfonamide group), an acyloxy group (such as an acetyloxy orbenzoyloxy group), a sulfonyloxy group (such as a methanesulfonyloxygroup), a ureido group (such as an unsubstituted ureido, methylureido,ethylureido, or phenylureido group), an acyl group (such as an acetyl orbenzoyl group), an oxycarbonyl group (such as a methoxycarbonyl orphenoxycarbonyl group), an oxycarbonylamino group (such as amethoxycarbonylamino, phenoxycarbonylamino, or2-ethylhexyloxycarbonylamino group), a hydroxyl group, or the like, andthe groups may be further substituted or unsubstituted. One ring mayhave a plurality of the substituents.

Preferred specific examples of the nitrogen-containing heterocycliccompounds include imidazole, benzimidazole, benzindazole, benzotriazole,benzoxazole, benzothiazole, pyridine, quinoline, pyrimidine, piperidine,piperazine, quinoxaline, and morpholine. These compounds may have asubstituent such as an alkyl group, a carboxyl group, or a sulfo group.

The nitrogen-containing 6-membered heterocyclic compound preferably hasa triazine ring, a pyrimidine ring, a pyridine ring, a pyrroline ring, apiperidine ring, a pyridazine ring, or a pyrazine ring, particularlypreferably has a triazine ring or a pyrimidine ring. Thenitrogen-containing 6-membered heterocyclic compound may have asubstituent, which may be a lower alkyl group having a carbon number of1 to 6 (more preferably 1 to 3), a lower alkoxy group having a carbonnumber of 1 to 6 (more preferably 1 to 3), a hydroxyl group, a carboxylgroup, a mercapto group, an alkoxyalkyl group having a carbon number of1 to 6 (more preferably 1 to 3), a hydroxyalkyl group having a carbonnumber of 1 to 6 (more preferably 1 to 3), etc.

Preferred specific examples of the nitrogen-containing 6-memberedheterocyclic compounds include triazine, methyltriazine,dimethyltriazine, hydroxyethyltriazine, pyrimidine, 4-methylpyrimidine,pyridine, and pyrroline.

The organic mercapto compound may be an alkylmercapto compound, anarylmercapto compound, a heterocyclic mercapto compound, or the like.The alkylmercapto compound may be cysteine, thiomalic acid, or the like,the arylmercapto compound may be thiosalicylic acid or the like, and theheterocyclic mercapto compound may be 2-phenyl-1-mercaptotetrazole,2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole,2-mercaptopyrimidine, 2,4-dimercaptopyrimidine, 2-mercaptopyridine, orthe like. These compounds may have a substituent such as an alkyl group,a carboxyl group, or a sulfo group.

A method for bringing the migration inhibitor into contact with thesupport having the conductive portion is not particularly limited. Forexample, the migration inhibitor may be applied to the support, oralternatively the support having the conductive portion may be immersedin the migration inhibitor.

The migration inhibitor may be dissolved in a solvent to prepare asolution if necessary. The type of the solvent is not particularlylimited, and the solvent may be selected from above-described examplesfor the photosensitive layer forming composition. The contact time isnot particularly limited, and is preferably 0.5 to 10 minutes, morepreferably 1.0 to 3.0 minutes.

(Organic Solvent Contact Process)

After the development treatment and any one of the above-describedprocesses, a process for bringing the support having the conductiveportion into contact with an organic solvent is preferably carried out.By performing this process, a macromolecule film remaining in theconductive portion or the non-conductive portion can be furtherdensified, the transparent conductive film 10 can be obtained with anexcellent ion migration inhibition ability, and the haze of thetransparent conductive film 10 can be reduced.

The type of the organic solvent to be used is not particularly limited,and an optimum solvent may be selected depending on the type of themacromolecule. In particular, the organic solvent is preferably asolvent in which the macromolecule can be dissolved to further improvethe above effect. The dissolution means that at least 5 g of themacromolecule is dissolved in 1 L (liter) of the organic solvent. Inparticular, the organic solvent preferably has an SP value of 8 to 12.Specific examples of the organic solvents include benzyl alcohol,ethanol, toluene, methyl ethyl ketone, acetone, and ethyl acetate.

The method for contacting the support having the conductive portion withthe organic solvent is not particularly limited, and may be selectedfrom known methods. For example, the organic solvent may be applied tothe support, or alternatively the support having the conductive portionmay be immersed in the organic solvent. The organic solvent contact timeis not particularly limited, and is preferably 10 to 60 minutes, morepreferably 15 to 30 minutes.

[Other Optional Process]

After the development treatment and any one of the above-describedprocesses, the physical development treatment and/or the platingtreatment for depositing the conductive metal particles on theconductive portion may be carried out to improve the conductivity of theconductive portion. In the present invention, the conductive metalparticles may be deposited on the conductive portion by only one of thephysical development and plating treatments or by the combination of thetreatments.

In this embodiment, the physical development is such a process thatmetal ions such as silver ions are reduced by a reducing agent, wherebymetal particles are deposited on a metal or metal compound core. Suchphysical development has been used in the fields of instant B & W film,instant slide film, printing plate production, etc., and thetechnologies can be used in the present invention.

In this embodiment, the plating treatment may contain electrolessplating (such as chemical reduction plating or displacement plating).Known electroless plating technologies for printed circuit boards, etc.may be used in this embodiment. The electroless plating is preferablyelectroless copper plating.

The present invention may be appropriately combined with technologiesdescribed in the following patent publications and international patentpamphlets shown in Tables 1 and 2. “Japanese Laid-Open Patent”,“Publication No.”, “Pamphlet No.”, etc. are omitted.

TABLE 1 2004-221564 2004-221565 2007-200922 2006-352073 2006-2284692007-235115 2007-207987 2006-012935 2006-010795 2007-072171 2006-3324592009-21153 2007-226215 2006-261315 2006-324203 2007-102200 2006-2284732006-269795 2006-336090 2006-336099 2006-228478 2006-228836 2007-0093262007-201378 2007-335729 2006-348351 2007-270321 2007-270322 2007-1789152007-334325 2007-134439 2007-149760 2007-208133 2007-207883 2007-0131302007-310091 2007-116137 2007-088219 2008-227351 2008-244067 2005-3025082008-218784 2008-227350 2008-277676 2008-282840 2008-267814 2008-2704052008-277675 2008-300720 2008-300721 2008-283029 2008-288305 2008-2884192009-21334 2009-26933 2009-4213 2009-10001 2009-16526 2008-1715682008-198388 2008-147507 2008-159770 2008-159771 2008-235224 2008-2354672008-218096 2008-218264 2008-224916 2008-252046 2008-277428 2008-2419872008-251274 2008-251275 2007-129205

TABLE 2 2006/001461 2006/088059 2006/098333 2006/098336 2006/0983382006/098335 2006/098334 2007/001008

EXAMPLES

The present invention will be described more specifically below withreference to Examples. Materials, amounts, ratios, treatment contents,treatment procedures, and the like, used in Examples, may beappropriately changed without departing from the scope of the presentinvention. The following specific examples are therefore to beconsidered in all respects as illustrative and not restrictive.

First Example

In Examples 1 to 15 and Comparative Examples 1 to 14, various propertieswere evaluated under various surface shapes of mat members used in acalender treatment.

Example 1

[Preparation of Silver Halide Emulsion]

Liquid 1 was maintained at 38° C. and pH 4.5, and 90% of the totalamounts of Liquids 2 and 3 were simultaneously added to Liquid 1 over 20minutes under stirring to form 0.16-μm nuclear particles. Then, Liquids4 and 5 were added thereto over 8 minutes, and residual 10% of Liquids 2and 3 were added over 2 minutes, so that the nuclear particles weregrown to 0.21 μm. Further 0.15 g of potassium iodide was added thereto,and the resulting mixture was aged for 5 minutes to complete theparticle formation.

<Liquid 1> Water 750 ml Gelatin 8.6 g Sodium chloride 3.1 g1,3-Dimethylimidazolidine-2-thione 20 mg Sodium benzenethiosulfonate 10mg Citric acid 0.7 g

<Liquid 2> Water 300 ml Silver nitrate 150 g

<Liquid 3> Water 300 ml Sodium chloride 38 g Potassium bromide 32 gPotassium hexachloroiridate (III) 5 ml (0.005% KCl, 20% aqueoussolution) Ammonium hexachlororhodate 7 ml (0.001% NaCl, 20% aqueoussolution)

<Liquid 4> Water 100 ml Silver nitrate  50 g

<Liquid 5> Water 100 ml Sodium chloride 13 g Potassium bromide 11 gPotassium ferrocyanide 5 mg

The resultant was water-washed by a common flocculation method.Specifically, the temperature was lowered to 35° C., the pH was loweredby sulfuric acid until the silver halide was precipitated (within a pHrange of 3.6±0.2), and about 3 L of the supernatant solution was removed(first water washing). Further 3 L of a distilled water was addedthereto, sulfuric acid was added until the silver halide wasprecipitated, and 3 L of the supernatant solution was removed again(second water washing). The procedure of the second water washing wasrepeated once more (third water washing), whereby the water washing anddesalting process was completed. After the water washing and desaltingprocess, the obtained emulsion was controlled at a pH of 6.3 and a pAgof 7.4. 2.5 g of a gelatin, 10 mg of sodium benzenethiosulfonate, 3 mgof sodium benzenethiosulfinate, 15 mg of sodium thiosulfate, and 10 mgof chlorauric acid were added thereto, whereby the emulsion waschemically sensitized at 55° C. to obtain the optimum sensitivity.Further 100 mg of a stabilizer of 1,3,3a,7-tetraazaindene and 100 mg ofan antiseptic agent of PROXEL (trade name, available from ICI Co., Ltd.)were added thereto, to obtain a final emulsion of cubic silveriodochlorobromide particles, which contained 0.08 mol % of silver iodideand silver chlorobromide including 70 mol % of silver chloride and 30mol % of silver bromide, and had an average particle diameter of 0.21 μmand a variation coefficient of 9.5%.

(Preparation of Composition for Forming Photosensitive Layer)

1.2×10⁻⁴ mol/mol-Ag of 1,3,3a,7-tetraazaindene, 1.2×10⁻² mol/mol-Ag ofhydroquinone, 3.0×10⁻⁴ mol/mol-Ag of citric acid, 0.90 g/mol-Ag of asodium salt of 2,4-dichloro-6-hydroxy-1,3,5-triazine, and a trace of afilm hardener were added to the emulsion, and the pH of the resultantcoating liquid was controlled to 5.6 using citric acid.

The polymer (P-1) included in the above specific examples of thepolymers represented by the general formula (1) and a disperser of adialkylphenyl PEO sulfuric ester were added to the gelatin in thecoating liquid. The amount of a crosslinking agent was controlled insuch a manner that a crosslinking agent content of 0.09 g/m² wasobtained in a photosensitive silver halide-containing layer to behereinafter described. A composition for forming a photosensitive layerwas prepared in this manner.

The polymer (P-1) was synthesized with reference to Japanese Patent Nos.3305459 and 3754745.

(Step of Forming Photosensitive Layer)

The above polymer latex was applied to a 100-μm polyethyleneterephthalate (PET) film (a transparent substrate 12), to form anundercoat layer having a thickness of 0.05 μm.

Then, a composition for forming a silver halide-free layer, whichcontained a mixture of the polymer latex and a gelatin, was applied tothe undercoat layer, to form a silver halide-free layer with a thicknessof 1.0 μm. The mixing ratio of the polymer to the gelatin (thepolymer/gelatin ratio) was 2/1 by mass, and the content of the polymerwas 0.65 g/m².

The composition for forming the photosensitive layer was applied to thesilver halide-free layer, to form a photosensitive silverhalide-containing layer with a thickness of 2.5 μm. The photosensitivesilver halide-containing layer had a polymer content of 0.22 g/m².

A composition for forming a protective layer, which contained a mixtureof the polymer latex and a gelatin, was applied to the photosensitivesilver halide-containing layer, to form a protective layer with athickness of 0.15 μm. The mixing ratio of the polymer to the gelatin(the polymer/gelatin ratio) was 0.1/1 by mass, and the content of thepolymer was 0.015 g/m².

(Exposure and Development Treatments)

Thus-obtained photosensitive layer was exposed to a parallel light froma light source of a high-pressure mercury lamp through a photomaskhaving a square lattice pattern for forming a conductive patterncontaining two square lattices arranged in parallel with a ratio ofconductive portion/non-conductive portion being 4.0 μm/296 μm(hereinafter referred to also as a mesh pattern electrode 42). The meshpattern electrode 42 is schematically shown in FIG. 10A. In thestructure of the mesh pattern electrode 42, two electrode patterns 48,which each contain twenty square lattices 46 connected in one directionbetween two terminals 44 a and 44 b, are arranged in parallel. Thus, themesh pattern electrode 42 contains forty square lattices 46 in total.Dot ellipsis shown in the center of each electrode pattern 48 means thatthe square lattices 46 are continuously connected. The distance betweenthe electrode patterns 48 is 5 mm, and the distance between theterminals 44 a and 44 b is 85 mm. As shown in FIG. 10B, the thin metalwires 24 in the square lattices 46 have a line width Wb of 4 μm, and thedistance between the thin metal wires 24 in each square lattice 46 (theside length of the light-transmitting portion) is 296 μm.

After the exposure, the exposed layer was developed using the followingdeveloper, fixed using a fixer N3X-R for CN16X (trade name, availablefrom FUJIFILM Corporation), rinsed with pure water, and dried, to obtaina sample having the mesh pattern electrode 42 with a thickness tc of 2.5μm (hereinafter referred to as the mesh sample). In a continuity test, atester was attached to the terminals 44 a and 44 b on the mesh patternelectrode 42 to measure the wiring resistance.

Furthermore, the photosensitive layer was prepared in the same manner asabove and exposed without the photomask. Then, the exposed layer wasdeveloped, fixed, rinsed, and dried in the same manner as the meshpattern electrode 42, to obtain a sample without the pattern for a lightreflection property measurement (hereinafter referred to as the solidsample).

(Developer Composition)

1 liter (L) of the developer contained the following compounds.

Hydroquinone 0.037 mol/L N-methylaminophenol 0.016 mol/L Sodiummetaborate 0.140 mol/L Sodium hydroxide 0.360 mol/L Sodium bromide 0.031mol/L Potassium metabisulfite 0.187 mol/L(Gelatin Decomposition Treatment)

Each of the mesh sample and the solid sample was immersed for 90 secondsin an aqueous solution containing 0.36 mM (mmol/L) of sodiumhypochlorite, and rinsed with pure water.

(Reduction Treatment)

Each of the mesh sample and the solid sample was immersed for 360seconds in the following reduction treatment liquid, washed with purewater, and dried.

<Composition of Reduction Treatment Liquid>

1 liter (L) of the reduction treatment liquid contained the followingcompounds.

Hydroquinone 0.20 mol/L Potassium hydroxide 0.45 mol/L Potassiumcarbonate 0.24 mol/L(Calender Treatment)

A metal plate 32A (stainless plate) having a surface shape with Ra of0.28 μm and Sm of 1.87 μm was used as a mat member 32 for the calendertreatment. In the calender treatment, the mesh sample having a width of6 cm was placed on the metal plate 32A, and a jack pressure of 11.4 MPawas applied to the stack using a calender apparatus containing acombination of a metal roller having a diameter of 95 mm and amirror-finished surface and a resin roller having a diameter of 95 mmwhile the stack was conveyed at a rate of 120 mm/minute. The solidsample was subjected to the calender treatment in the same manner.

(Heating Treatment)

Each of the mesh sample and the solid sample was treated for 130 secondswith a superheated vapor bath having a temperature of 120° C., to obtaina mesh sample and a solid sample according to Example 1.

[Various Evaluations]

(Surface Shape Evaluation)

The surface shape properties (Ra and Sm) of the solid samples and matmembers 32 (metal plates 32A and resin films 32B) used in the calendertreatment were measured as follows.

First, in each of the mat members 32 and the solid samples, micrographsof arbitrarily-selected five areas were taken at an object lensmagnification of 100 using an ultra-deep shape measuring microscopeVK8550 available from KEYENCE. Then, the horizontal line roughnesses(147 μm) of two positions in each area were measured using a shapeanalysis application of the microscope (JIS-B-0601-1994). The minimumand maximum values were removed from ten values measured in each of themat members 32 and the solid samples, and the average of the remainingeight values was considered as the line roughness of each sample. Rarepresents an arithmetic average roughness determined in this manner,and Sm represents an average distance between convex portions. In theroughness measurement, tilt correction of the sample was performed ifnecessary, but cutoff setting and smoothing of the roughness curve werenot performed.

(Volume Content Evaluation)

The metal volume content of the solid sample was measured as follows.First, the solid sample was punched, and the punched solid sample havinga size of 1 cm square was immersed and stirred at the room temperaturefor 30 minutes in 100 cc of a solution, which was prepared by mixing 150cc of 10% sulfuric acid, 8 g of cerium sulfate tetrahydrate, and 300 ccof pure water. Complete decoloration of the solid sample was confirmed,and then the amount of the silver eluted into the solution was measuredusing an ICP mass spectrometer (ICPM-8500 available from ShimadzuCorporation) to obtain the silver amount per unit area W [g/m²] in thecoating film.

Then, the solid sample was cut by a microtome, and the cut surface wasobserved by a scanning electron microscope SEM (JSM-6500F available fromJEOL Ltd.) Ten areas were arbitrarily selected and observed to measurethe average thickness H [m] of the silver layer.

The silver amount per unit volume of the silver layer in the solidsample was calculated by W/H [g/m³]. In a case where the silver layer isfree from voids and organic substances, the volume content is 100%, andthe metallic silver density is 10.49×10⁻⁶ g/cm³ (Essential ChemicalDictionary, 1999, Tokyo Kagaku Dojin). Therefore, the silver volumecontent of the silver layer was calculated by W/H/(10.49×10⁻⁶)×100 [%].

(Optical Property Evaluation)

<Specular Reflectance>

The specular reflectance of the solid sample was measured as follows.First, the reflection spectrum was measured using an ultraviolet andvisible spectrophotometer V660 (a single reflection measurement unitSLM-736) available from JASCO Corporation under conditions of ameasurement wavelength of 350 to 800 nm and an incident angle of 5degrees. In this measurement, a specularly reflected light of analuminum-vapor-deposited plane mirror was used for a baseline. The Yvalue in a 2 degree field of a D65 light source in the XYZ color system(the color-matching function according to JIS Z9701-1999) was calculatedas the specular reflectance from the obtained reflection spectrum usinga color calculation program available from JASCO Corporation.

In a case where the specular reflectance is less than 3%, advantageouslythe thin metal wire 24 in the mesh pattern electrode 42 is less visible.In a case where the specular reflectance is less than 1%, furtheradvantageously the thin metal wire 24 is significantly less visible. Ina case where the specular reflectance is 3% or more, the thin metal wire24 is highly visible and is not suitable for practical use.

<Total Light Transmittance>

The total light transmittance of the solid sample was measured asfollows. First, the total light reflection spectrum including thespecularly reflected light and diffusion lights was measured using anultraviolet and visible spectrophotometer V660 (an integrating sphereunit ISV-722) available from JASCO Corporation within a measurementwavelength range of 350 to 800 nm. In this measurement, Spectralon™available from Labsphere was used as a standard white plate for abaseline. The Y value in a 2 degree field of a D65 light source in theXYZ color system (the color-matching function according to JISZ9701-1999) was calculated as the total light transmittance from theobtained reflection spectrum using a color calculation program availablefrom JASCO Corporation.

<Visual Detection Difficulty of Pattern>

The calender-treated surface of the mesh sample was attached to a whiteglass plate by a 50-μm transparent optical adhesive film (8146-2available from 3M Company). Furthermore, a 100-μm PET film was attachedto the other surface of the mesh sample by the same 50-μm transparentoptical adhesive film. The mesh sample, sandwiched between the glass andthe PET film, was placed on a black paper surface in such a manner thatthe thin metal wire 24 was at the front, i.e. the glass surface was theuppermost surface. The visual detection difficulty of the pattern wascomprehensively evaluated under irradiation of a fluorescent lamp or asolar light while changing the directions of the light incidence andpattern observation.

A: The mesh pattern was less visible, and did not cause practicalproblems.

B: The mesh pattern was visible at a particular angle under the intenselight source (sunlight), but did not cause practical problems.

C: The mesh pattern was visible at a particular angle even under theweak light source (fluorescent lamp), but did not cause practicalproblems.

D: The light reflection of the mesh pattern was highly visible, andcauses a practical problem.

(Continuity Evaluation)

The electrical resistance of the wiring in the mesh pattern electrode 42was measured using a digital multi-meter (M3500 available fromPICOTEST). Five samples of the mesh pattern electrode 42 shown in FIG.10A were prepared, and the average of the measured resistance values ofthe samples was considered as the wiring resistance of the mesh patternelectrode 42. The obtained wiring resistance value was divided by thatof Comparative Example 1, in which the calender treatment was notcarried out, and was evaluated as compared with Comparative Example 1.When a mesh pattern electrode was evaluated as “D”, this sample couldnot achieve a function as the transparent conductive film. Thus, thesample could not transmit the visible lights and could not achieve anelectric continuity, and was judged not to be a transparent conductivefilm.

A: The wiring resistance value was at most 0.4 times as large as that ofthe mesh wiring of Comparative Example 1.

B: The wiring resistance value was at most 1.0 time as large as that ofthe mesh wiring of Comparative Example 1.

C: The wiring resistance value was more than 1.0 time as large as thatof the mesh wiring of Comparative Example 1.

D: The wiring resistance value was excessively high and could not bemeasured.

(Adhesion Evaluation)

The adhesion of the solid sample was evaluated by a cross-cut testaccording to JIS-K-5600. The adhesion was evaluated according to thefollowing criteria.

A: Peeling was not caused.

D: Peeling was caused.

Example 2

A mesh sample and a solid sample of Example 2 were produced in the samemanner as Example 1 except for using a metal plate 32A having a surfaceshape with Ra of 0.23 μm and Sm of 2.16 μm (a chromium-plated stainlessplate) as the mat member 32 in the calender treatment.

Example 3

A mesh sample and a solid sample of Example 3 were produced in the samemanner as Example 1 except for using a metal plate 32A having a surfaceshape with Ra of 0.20 μm and Sm of 2.21 μm (a chromium-plated stainlessplate) as the mat member 32 in the calender treatment.

Example 4

A mesh sample and a solid sample of Example 4 were produced in the samemanner as Example 1 except for using a metal plate 32A having a surfaceshape with Ra of 1.29 μm and Sm of 11.54 μm (a chromium-plated stainlessplate) as the mat member 32 in the calender treatment.

Example 5

A mesh sample and a solid sample of Example 5 were produced in the samemanner as Example 1 except for using a metal plate 32A having a surfaceshape with Ra of 1.08 μm and Sm of 12.32 μm (a chromium-plated stainlessplate) as the mat member 32 in the calender treatment.

Example 6

A mesh sample and a solid sample of Example 6 were produced in the samemanner as Example 1 except for using a metal plate 32A having a surfaceshape with Ra of 1.82 μm and Sm of 13.91 μm (a chromium-plated stainlessplate) as the mat member 32 in the calender treatment.

Example 7

A mesh sample and a solid sample of Example 7 were produced in the samemanner as Example 1 except for using a metal plate 32A having a surfaceshape with Ra of 1.27 μm and Sm of 15.58 μm (a chromium-plated stainlessplate) as the mat member 32 in the calender treatment.

Example 8

A mesh sample and a solid sample of Example 8 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 0.23 μm and Sm of 1.89 μm (a PET film) as the matmember 32 in the calender treatment.

Example 9

A mesh sample and a solid sample of Example 9 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 0.72 μm and Sm of 5.54 μm (a PET film) as the matmember 32 in the calender treatment.

Example 10

A mesh sample and a solid sample of Example 10 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 0.60 μm and Sm of 4.30 μm (a PET film) as the matmember 32 in the calender treatment.

Example 11

A mesh sample and a solid sample of Example 11 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 0.27 μm and Sm of 5.29 μm (a PET film) as the matmember 32 in the calender treatment.

Example 12

A mesh sample and a solid sample of Example 12 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 0.49 μm and Sm of 4.86 μm (a PET film) as the matmember 32 in the calender treatment.

Example 13

A mesh sample and a solid sample of Example 13 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 0.57 μm and Sm of 7.33 μm (a PET film) as the matmember 32 in the calender treatment.

Example 14

A mesh sample and a solid sample of Example 14 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 0.64 μm and Sm of 3.41 μm (a PET film) as the matmember 32 in the calender treatment.

Example 15

A mesh sample and a solid sample of Example 15 were produced in the samemanner as Example 1 except for using a resin film 32B having a surfaceshape with Ra of 1.41 μm and Sm of 4.89 μm (a PET film) as the matmember 32 in the calender treatment.

Comparative Example 1

A mesh sample and a solid sample of Comparative Example 1 were producedin the same manner as Example 1 except for not performing the calendertreatment.

Comparative Example 2

A mesh sample and a solid sample of Comparative Example 2 were producedin the same manner as Example 1 except for using a resin film 32B havinga surface shape with Ra of 0.03 μm and Sm of 0.86 μm (a PET film) as themat member 32 in the calender treatment.

Comparative Example 3

A mesh sample and a solid sample of Comparative Example 3 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.15 μm and Sm of 1.91 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 4

A mesh sample and a solid sample of Comparative Example 4 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.13 μm and Sm of 1.90 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 5

A mesh sample and a solid sample of Comparative Example 5 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.11 μm and Sm of 2.28 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 6

A mesh sample and a solid sample of Comparative Example 6 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.15 μm and Sm of 2.19 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 7

A mesh sample and a solid sample of Comparative Example 7 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.49 μm and Sm of 4.07 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 8

A mesh sample and a solid sample of Comparative Example 8 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.32 μm and Sm of 3.67 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 9

A mesh sample and a solid sample of Comparative Example 9 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.31 μm and Sm of 3.19 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 10

A mesh sample and a solid sample of Comparative Example 10 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.59 μm and Sm of 4.76 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 11

A mesh sample and a solid sample of Comparative Example 11 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.41 μm and Sm of 3.09 μm (achromium-plated stainless plate) as the mat member 32 in the calendertreatment.

Comparative Example 12

A mesh sample and a solid sample of Comparative Example 12 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.79 μm and Sm of 41.13 μm (astainless plate) as the mat member 32 in the calender treatment.

Comparative Example 13

A mesh sample and a solid sample of Comparative Example 13 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.38 μm and Sm of 13.42 μm (astainless plate) as the mat member 32 in the calender treatment.

Comparative Example 14

A mesh sample and a solid sample of Comparative Example 14 were producedin the same manner as Example 1 except for using a metal plate 32Ahaving a surface shape with Ra of 0.28 μm and Sm of 8.04 μm (a stainlessplate) as the mat member 32 in the calender treatment.

(Evaluation Results)

The properties and evaluation results of Examples 1 to 15 andComparative Examples 1 to 14 are shown in Table 3. It should be notedthat [um] represents the unit [μm] in Table 3.

TABLE 3 Transparent conductive film Solid sample Calender surfaceSpecular Surface shape reflectance Mesh sample Ra²/ Ra²/ Volume Specularof back Total light Wiring Ra Sm Sm Ra Sm Sm content reflectance surfacetransmittance resistance Pattern Material [um] [um] [um] [um] [um] [um][%] [%] [%] [%] ratio Adhesion visibility Example 1 SUS 0.28 1.87 0.0380.19 3.05 0.012 52 0.6 0.8 22.2 A A A Example 2 SUS/Cr 0.23 2.16 0.0230.20 2.63 0.015 52 0.6 0.8 21.2 A A A platin Example 3 SUS/Cr 0.20 2.210.019 0.16 2.29 0.012 52 1.2 0.8 22.6 A A B platin Example 4 SUS/Cr 1.2911.54 0.145 0.28 5.72 0.014 42 2.3 0.8 23.4 B A C platin Example 5SUS/Cr 1.08 12.32 0.095 0.32 6.25 0.016 44 1.8 0.8 24.0 B A C platinExample 6 SUS/Cr 1.82 13.91 0.238 0.38 4.88 0.029 42 2.8 0.8 22.6 B A Cplatin Example 7 SUS/Cr 1.27 15.58 0.103 0.31 5.27 0.018 48 1.9 0.8 22.3B A C platin Example 8 PET 0.23 1.89 0.027 0.17 2.05 0.014 52 0.4 0.818.9 A A A Example 9 PET 0.72 5.54 0.094 0.26 3.58 0.018 53 0.6 0.8 17.9A A A Example 10 PET 0.60 4.30 0.083 0.26 3.45 0.020 55 0.8 0.8 21.4 A AA Example 11 PET 0.27 5.29 0.014 0.19 3.37 0.011 55 2.8 0.8 19.6 A A BExample 12 PET 0.49 4.86 0.049 0.25 2.86 0.022 53 0.7 0.8 18.7 A A AExample 13 PET 0.57 7.33 0.045 0.30 3.17 0.028 52 0.7 0.8 18.9 A A AExample 14 PET 0.64 3.41 0.118 0.25 3.38 0.018 52 0.6 0.8 17.6 A A AExample 15 PET 1.41 4.89 0.404 0.22 2.92 0.016 50 0.5 0.8 16.6 B A ACom. Ex. 1 N/A — — — 0.21 2.33 0.020 30 0.5 0.6 13.1 B D A Com. Ex. 2PET 0.03 0.86 0.001 0.09 2.74 0.003 63 11.3 0.8 21.0 A A D Com. Ex. 3SUS/Cr 0.15 1.91 0.011 0.13 2.40 0.007 53 3.8 0.8 21.6 A A D platin Com.Ex. 4 SUS/Cr 0.13 1.90 0.008 0.13 2.07 0.008 53 4.6 0.8 22.5 A A Dplatin Com. Ex. 5 SUS/Cr 0.11 2.28 0.005 0.10 2.36 0.004 52 9.3 0.8 23.0A A D platin Com. Ex. 6 SUS/Cr 0.15 2.19 0.010 0.11 2.13 0.006 52 3.50.8 22.5 A A D platin Com. Ex. 7 SUS/Cr 0.49 4.07 0.060 0.32 3.89 0.02648 0.6 0.8 21.0 D A A platin Com. Ex. 8 SUS/Cr 0.32 3.67 0.028 0.25 2.840.023 48 0.7 0.8 21.1 D A A platin Com. Ex. 9 SUS/Cr 0.31 3.19 0.0300.18 2.52 0.013 47 0.6 0.8 20.6 D A A platin Com. Ex. 10 SUS/Cr 0.594.76 0.073 0.22 3.09 0.016 48 0.6 0.8 21.2 D A A platin Com. Ex. 11SUS/Cr 0.41 3.09 0.054 0.26 2.92 0.023 50 0.6 0.8 20.9 D A A platin Com.Ex. 12 SUS 0.79 41.13 0.015 0.19 4.54 0.008 53 5.0 0.8 22.7 A A D Com.Ex. 13 SUS 0.38 13.42 0.010 0.21 5.59 0.008 53 5.2 0.8 22.7 A A D Com.Ex. 14 SUS 0.28 8.04 0.010 0.17 5.63 0.005 53 7.4 0.8 22.4 A A D

As shown in Table 3, in all of Examples 1 to 15, the mesh samples hadgood wiring resistance ratios, adhesions, and visual pattern detectiondifficulties. In particular, in Examples 1, 2, 8 to 10, and 12 to 14,the mesh samples had excellent wiring resistance ratios, adhesions, andvisual pattern detection difficulties, evaluated as “A”. In Examples 8to 15, the resin films 32B (the PET films) were used as the mat member32, whereby the mesh samples had excellent properties totally. Forexample, in Example 3, the metal plate 32A was used as the mat member32, whereby the solid sample had a specular reflectance of 1.2%, and themesh sample had a visual detection difficulty evaluation result of “B”.Similarly, in Example 4, the metal plate 32A was used as the mat member32, whereby the solid sample had a specular reflectance of 2.3%, and themesh sample had a visual detection difficulty evaluation result of “C”.In contrast, for example, in Example 11, where the resin film 32B wasused as the mat member 32, though the solid sample had a specularreflectance of 2.8%, the mesh sample had a visual detection difficultyevaluation result of “B”. In Examples 4 to 7, the Sm values of thesurface shapes in the mat members 32 were larger than the width linewidth (4 μm) of the thin metal wire, and thus the Sm values of thesurface shapes in the solid samples were more than 4 μm, whereby thevisual pattern detection difficulties were evaluated as “C”, butpractical problems were not caused. Furthermore, in Examples 4 to 7, theRa values of the surface shapes in the mat members 32 were larger than ⅙(approximately 0.42 μm) of the thickness tc (2.5 μm) of the thin metalwire 24 measured before the calender treatment, the wiring resistanceratios were evaluated as “B”, but the electrical resistances wereadvantageously lower than that of Comparative Example 1.

Furthermore, the wiring resistance ratios of Examples 1 to 3 wereevaluated as “A”, and those of Comparative Examples 7 to 11 wereevaluated as “D”. The visual pattern detection difficulties of Examples1 and 2 were evaluated as “A”, that of Example 3 was evaluated as “B”,and those of Comparative Examples 3 to 6 and 12 to 14 were evaluated as“D”. FIG. 11 is a graph plotting the evaluation results ofrepresentative Examples 1 to 3 and Comparative Examples 3 to 6, 7 to 11,13, and 14, where the abscissa represents the Ra value of the pressingsurface of the metal plate, and the ordinate represents the Sm value ofthe pressing surface. Examples 1 to 3 had the most excellent evaluationresults, and Comparative Examples 3 to 6, 7 to 11, 13, and 14 had poorresults in the wiring resistance ratio or visual pattern detectiondifficulty evaluation. Comparative Example 12 had a high Sm value of41.13, and therefore the results were not plotted. The curve Lcrepresents Sm=Ra²/0.015.

As is clear from the results, in the transparent conductive film 10, itis preferred that a part of the metal wiring portion 14 having the meshpattern electrode 42 has a surface shape satisfying the condition ofRa²/Sm>0.01 μm and a metal volume content of 35% or more. Furthermore,it is more preferred that the part having the mesh pattern electrode 42has an Sm value of 4 μm or less.

In addition, in the case of using the metal plate 32A as the mat member32 for the calender treatment, it is preferred that the metal plate hasan Ra²/Sm value of more than 0.015 μm. It is particularly preferred thatthe metal plate has an Sm value equal to or smaller than the line widthWb of the thin metal wire 24, an Ra value equal to or smaller than ⅙ ofthe thickness tc of the thin metal wire 24 measured before the calendertreatment, and an Ra²/Sm value of more than 0.015 μm.

On the other hand, in the case of using the resin film 32B as the matmember 32 for the calender treatment, it is preferred that the resinfilm has a surface shape with an Ra value of more than 0.15 μm.Furthermore, it is preferred that the resin film has an Ra²/Sm value ofmore than 0.01 μm.

In the above Examples, the evaluation results were obtained in the caseof using the mat member 32 in the calender treatment. Similar evaluationresults could be obtained also in the case of using a calender apparatuscontaining a combination of a metal roller having a roughened surfaceand a resin roller having a mirror-finished surface, without the matmember 32. In this case, in the calender treatment, a jack pressure of11.4 MPa was applied while the mesh or solid sample was conveyed at aspeed of 120 mm/minute. In this treatment, the metal portion of the meshor solid sample was brought into contact with the metal roller. In theevaluation of the surface properties of the metal roller, an end of themetal roller was cut to prepare a small sample that could be placed on astage of the microscope.

Supposing that the metal roller is cut, the resultant metal rollercannot be used for the production. Thus, it is substantially impossibleto evaluate the uncut metal roller for the production by cutting out themetal roller. The surface shape (surface roughness) of the metal roller,however, can be measured by transferring the surface shape to a film andby evaluating the surface shape of the film in the following manner.

First, a 40-μm-thick film of triacetylcellulose (hereinafter referred toas TAC) is immersed in acetone for 5 seconds. After the immersion inacetone, the TAC is gently overlaid on the metal roller while preventingbubble introduction, and is then air-dried. After the drying, the TAC isslowly peeled off. Then, the surface shape of the metal roller istransferred to the TAC. The surface roughness of the transferred surfaceof the TAC is measured using the laser microscope in the same manner asthe surface shape evaluation method of Example 1, whereby the surfaceroughness of the metal roller is determined. The surface roughness Raand Sm of the transferred surface of the TAC correspond perfectly tothose of the original surface of the metal roller, and it is notnecessary to correct the measured values.

Second Example

In Examples 16 and 17 and Comparative Example 15, various propertieswere evaluated under various surface shapes of supports. The propertiesand evaluation results of Examples 16 and 17 and Comparative Example 15are shown in Table 4. It should be noted that [um] represents the unit[μm] also in Table 4.

Example 16

(1. Formation of Plating Base Polymer Layer Containing Reduced MetalParticles)

[Preparation of Composition for Forming Plating Base Polymer Layer]

7.1% by mass of an acrylic polymer was dissolved in a mixture solvent of73% by mass of 1-methoxy-2-propanol and 19.9% by mass of water toprepare a solution. 0.35% by mass of a photopolymerization initiator(ESACURE KTO-46 available from Lamberti) was further added to thesolution, and the resultant was stirred to prepare a plating basepolymer solution.

The plating base polymer solution was applied to a PET film having asurface shape with Ra of 0.23 μm and Sm of 1.89 μm (available fromFUJIFILM Corporation) by a bar coating method, the thickness of theapplied solution being about 0.55 μm. The applied solution was dried atthe room temperature for 10 minutes and further dried at 80° C. for 5minutes, and was exposed to a UV light under conditions of at 254-nmwavelength and 1000 mJ/cm² by a UV irradiation device (a metal halidelamp available from GS Yuasa International Ltd.) A mesh pattern mask wasused in the UV exposure for forming a mesh pattern electrode.

The resultant substrate of the PET film coated with the plating basepolymer was immersed in an aqueous solution containing 1% by mass ofsodium hydrogen carbonate for 5 minutes, and was washed with a purewater flow for 1 minute to remove the unreacted polymer.

(2. Deposition of Metal Precursor)

An aqueous solution containing 1% by mass of silver nitrate was preparedas a solution containing a plating metal precursor. The substrate of thePET film applied with the plating base polymer, prepared in the abovestep, was immersed in the metal precursor solution for 5 minutes, andthen washed with a pure water flow for 1 minute, whereby the metalprecursor was deposited.

(3. Reduction of Metal Precursor)

An aqueous solution containing a mixture of 0.25% by mass offormaldehyde and 0.14% by mass of sodium hydroxide was prepared as areducing solution. The substrate of the PET film having the metalprecursor, prepared in the above step, was immersed in the reducingsolution for 1 minute, and was washed with a pure water flow for 1minute, whereby the metal precursor was reduced.

(4. Electroplating)

In a pretreatment for electroplating, the substrate of the PET filmhaving the reduced metal on the surface, prepared in the above step, wasimmersed in an aqueous solution containing 10% by mass of Dain CleanerAC100 (available from Daiwa Fine Chemicals Co., Ltd.) for 30 seconds,and was washed with a pure water flow for 1 minute. In anotherpretreatment for the electroplating, the substrate was immersed in anaqueous solution containing 10% by mass of Dain Silver ACC (availablefrom Daiwa Fine Chemicals Co., Ltd.) for 10 seconds, and was washed witha pure water flow for 1 minute.

Dain Silver Bright PL50 (available from Daiwa Fine Chemicals Co., Ltd.)was used as an electroplating liquid, and the pH was controlled at 9.0by an 8-M potassium hydroxide. The PET film substrate having thepretreated reduced metal on the surface was immersed in theelectroplating liquid, a plating treatment was carried out at 0.5 A/dm²for 20 seconds, and the resultant was washed with a pure water flow for1 minute.

In an aftertreatment of the electroplating, the plated PET filmsubstrate was immersed in an aqueous solution containing 10% by mass ofDain Silver ACC (available from Daiwa Fine Chemicals Co., Ltd.) for 90seconds, and was washed with a pure water flow for 1 minute.

A solid sample and a mesh sample, which had a silver layer with athickness of 200 nm, were obtained in this manner. The samples wereevaluated in the same manner as Example 1. As a result, the solid samplehad a specular reflectance of 2.1%, the metal portion had Ra of 0.18 μm,Sm of 2.21 μm, and a metal volume content of 97%, and the mesh samplehad a wiring resistance ratio of “A”, an adhesion of “A”, and a patternvisibility of “C”.

Example 17

Silver was vapor-deposited on a PET film having a surface shape with Raof 0.23 μm and Sm of 1.89 μm (available from Kaisei Industries, Inc.) byusing a vacuum deposition apparatus JEE-400 (available from JEOL Ltd.),the thickness of the deposited silver being 200 nm.

The solid and mesh samples were evaluated in the same manner asExample 1. As a result, the solid sample had a specular reflectance of3.4%, the metal portion had Ra of 0.17 μm, Sm of 2.42 μm, and a metalvolume content of 97%, and the mesh sample had a wiring resistance ratioof “A”, an adhesion of “A”, and a pattern visibility of “C”.

Comparative Example 15

A solid sample and a mesh sample, which had a silver layer with athickness of 200 nm, were obtained in the same manner as Example 16except for using a PET film having a smoothened surface with Ra of 0.03μm and Sm of 0.83 μm (available from FUJIFILM Corporation) instead ofthe PET film having a surface shape with Ra of 0.23 μm and Sm of 1.89μm.

The solid and mesh samples were evaluated in the same manner asExample 1. As a result, the solid sample had a specular reflectance of73.3%, the metal portion had Ra of 0.04 μm, Sm of 1.10 μm, and a metalvolume content of 97%, and the mesh sample had a wiring resistance ratioof “A”, an adhesion of “A”, and a pattern visibility of “D”.

TABLE 4 Transparent conductive film Solid sample Support SpecularSurface shape reflectance Mesh sample Ra²/ Ra²/ Volume Specular of backTotal light Wiring Ra Sm Sm Ra Sm Sm content reflectance surfacetransmittance resistance Pattern Material [um] [um] [um] [um] [um] [um][%] [%] [%] [%] ratio Adhesion visibility Example PET film 0.23 1.890.028 0.18 2.21 0.015 97 2.1 0.8 22.2 A A C 16 Example PET film 0.231.89 0.028 0.17 2.42 0.012 97 3.4 0.8 21.2 A A C 17 Com. PET film 0.030.83 0.001 0.04 1.10 0.001 97 73.3 0.8 82.0 A A D Exam 15

As shown in Table 4, in both of Examples 16 and 17, the mesh samples hadexcellent wiring resistance ratios and adhesions evaluated as “A”.However, the specular reflectances were 2.1% and 3.4% respectively,similar to that of Example 4 in First Example. Therefore, the visualpattern detection difficulties were evaluated as “C”, but practicalproblems were not caused. The specular reflectance was lower in Example16 where the metal film was formed on the support by the platingtreatment than in Example 17 where the metal film was formed by thevapor deposition.

In Comparative Example 15, the metal film was formed on the smoothenedsurface, whereby the specular reflectance was a significantly high valueof 73.3%, and the visual pattern detection difficulty was evaluated as“D”, though the metal film was formed by the plating treatment.

As is clear from the results, also in the case of forming the metalwiring portion on the support having the concave-convex surface, theproducts could achieve the excellent properties similar to those ofExamples 3, 4, etc. in First Example. Furthermore, in comparison betweenExamples 16 and 17 and Comparative Example 15, it was confirmed that thevisibility could be more excellent in the case of forming the metalwiring portion on the support having the concave-convex surface than inthe case of forming the metal film on the smoothened surface.

It is to be understood that the transparent conductive film, thetransparent conductive film production method, the touch panel, and thedisplay device of the present invention are not limited to the aboveembodiments, and various changes and modifications may be made thereinwithout departing from the scope of the present invention.

The invention claimed is:
 1. A transparent conductive film comprising asupport and a metal wiring portion formed thereon, wherein at least apart of the metal wiring portion has a surface shape satisfying acondition of Ra²/Sm>0.01 μm and has a metal volume content of 35% ormore, the Ra represents an arithmetic average roughness in micrometersand is equal to or smaller than a thickness of a thin metal wire locatedin a position where a surface roughness is measured, the Sm representsan average distance between convex portions and is 0.01 μm or more, andat least the part of the metal wiring portion has a mesh patterncontaining the thin metal wire.
 2. The transparent conductive filmaccording to claim 1, wherein at least the part of the metal wiringportion has Sm of 4 μm or less.
 3. The transparent conductive filmaccording to claim 1, wherein at least the part of the metal wiringportion has a difference of less than 3% between the specularreflectances of a front surface and a back surface.
 4. The transparentconductive film according to claim 1, wherein the transparent conductivefilm is obtained by a production method containing: an exposure step ofexposing a photosensitive material having the support and a silver saltemulsion layer formed thereon; and a development step of developing theexposed silver salt emulsion layer to form a conductive patterncontaining a metallic silver portion on the support.